When a baby boy has his Bris we wish him "K'shaim Shenichnas L'Bris Kain Yikones L'Torah L'Chupa U'Lmaasim Tovim" - just like you entered the covenant so to should you enter into Torah, marriage, and good deeds. Should not Maasim Tovim be prior to Torah and Chupa? (Derech Eretz Kodma L'Torah)
Shaalos U'Teshuvos Atzei Broshim Siman 57 brings in the name of the Avudram and also in the Bais Yosef Yoreh Deah 265 that a parent has a Chiyuv to teach a child Torah and to make their Chuppa, and then it is the childs responsibility to do Maasim Tovim.
Likkuti Basar Likkuti (Agodas Hashas to Shabbos 137b) brings the following explanation from the author of "Iyun Menachem":
The Gemora (Kiddushin 29b) brings R' Yehuda in the name of Shmuel that one should marry first and then learn Torah, to which R' Yehuda responds that one is not able to learn Torah with the yoke of supporting his family. From this it is evident that before marriage it is easier to involve oneself in "Maasim Tovim" for then he has free time to learn Torah, and Chazal say (Kiddush 30) that "I created the Yetzer Horah, and I created the Torah as an antidote. If you involve yourselves in Torah you will not be given over to it." Since the obstacle to "Maasim Tovim" is the Yetzer Horah, and before marriage he had the Torah to protect him it was not so difficult to practise "Massim Tovim". However, after one gets married and assumes the yoke of supporting his family he is now susceptible to the Yetzer Horah who attempts to stop him from performing good deeds and he no longer has Torah to help. We therefore bless him that even after he gets married he should continue to do "Massim Tovim" despite the new difficulties.
It is known (Zohar Chelek Gimmel 257b, see Tur Orach Chaim end of Siman 417) that the three Avos correspond to the three festivals: Avraham, who characterized kindness, corresponds to the festival of Pesach when Hashem "passed over" the houses of the Jews and did not smite us. Yitzchok is the idea of severity, and the Torah was given on Shavuos "Mipi Hagevura", and Yaakov whose idea was Torah signifies the holiday of Sukkos (as Torah creates a "shade"- sukkah - for the soul).
We can similarly connect these three concepts to the three blessings of "Torah", "Chuppah" and "Massim Tovim". Avraham - kindness and charity - is "Massim Tovim". Yitzchok who is connected to Shavous, the marriage day between Hashem and the Jewish people, corresponds to "Chuppa", and Yaakov is the idea of "Torah".
In our personal G-dly service we need to emulate the actions of the three forefathers and thus must incorporate these three ideas. However, the balancing act between kindness and severity is often difficult - too much kindness can be inappropriate as can too much harshness. We balance the two by preceding the Chesed with Gevurah insuring that the kindness is directed to the proper channels. Thus the ideal order is to base ones actions on the directive of "Torah", which instructs us how and when to have the idea of "Chuppah" (Gevura) first, and then "Massim Tovim" (Chesed).
Alternatively, Likkutey Levi Yitzchok (Ha'aros to Sefer Hazohar, Breishis pg. 60, written by R' Levi Yitzchok Shnuerson, father of the Lubavitcher Rebbe) explains that Bris Milah corresponds to Rosh Hashana (a central theme of Rosh Hashana is the Zichronos of the "bris" between the Jewish people and Hashem commemorated by the blowing of the Shofar [see there for more connections between Rosh Hashana and Milah]). "Torah" corresponds to Yom Kippur when the second Luchos were given. The schach of Sukkos resembles the "Chuppah", and "Maasim Tovim" corresponds to Shmini Atzeres (he does not explain why).
The word shem (name) means the essence of an item. Thus we see when Adam gave "names" to the animals he recognized their essences and integrated them into his view of the world. Thus, just as the entry into the bris was because of the essence of the mitzvah and not any external influence, so too should the other main mitzvos and critical moments of life occur.
תורה Bar Mitzvah - entering into the mitzos
חופה - Wedding - creating a new family
מעשים טובים - Now he can really start the "good deeds" of his family initiating his son into mitzvos by performing his bris.
I have seen the following explanation.
לתורה Teach your son torah as he grows and he will become a talmid chacham
לחופה The next step is that he is to be married to an appropriate woman who will join with him as an אשת חיל
ןלמעשים טובים Now he can continue his life as a full adult. He can now fulfill the first mitzvah of a human being (פרו ורבו) by starting his own family and continuing the cycle. He can perform the mitzvos that he has learned from his father.
My own personal reason is that a child is not really an adult until after he has been married. Thus, a person is not really able to do "maasim tovim" until after the chupah. The maasim tovim are actually the deeds caused by raising and supporting a family (starting with his fulfillment of pru urvu). This begins the continuation of the chain of existence. The maasim tovim are the deed which include giving his sons a bris, teaching them (sons and daughters) torah and marrying them off.
Another explanation found at Understanding the Blessing given at a Bris Milah by Chaim B.
During the Bris Milah ceremony, the following blessing is given to the parents of the baby boy "כשם שנכנס לברית כן יכנס לתורה לחופה ולמעשים טובים" "In the same way that you entered the Bris, so should you enter marriage, Torah and good deeds"
What is the similarity between these three things?
Compromise! Or more specifically, compromising in order to develop a strong relationship.
The lesson from the Bris Milah is that compromise comes from giving something up to acquire something greater. Just like the baby is giving up a piece of himself to attain a spiritual relationship with God and a bond with the entire Jewish People, so too, a good marriage is based on each spouse giving up certain aspects of their life that aren’t conducive to marriage for the sake of developing a healthy relationship with each other.
Similarly, someone is only able to be successful in their Torah learning if they are able to give up their own sense of ‘how things should be’ and recognize the Divine superiority of the words they are learning.
And finally, “Maasim Tovim” which are the Mitzvos require sacrifice. Without giving of oneself, one cannot act with sincere compassion!
This is the understanding behind the blessing said at a Bris Milah – Just like we are seeing that this baby is giving of himself in order to attach himself to something greater, so too, this is how he should proceed for the rest of his life – something truly necessary to succeed in Torah, Marriage and Mitzvos.