Shalom, I was adopted before my birth, (birth by a non Jewish mother), into a Jewish family with a Jewish Mother, Father and sisters. I was raised as a Jew, had a Bat Mitzvah and have since become observant. I am Shabbos observant, eat Kosher (although my kitchen still awaits kashering). The family laws of purity, (niddah), I have been told don't apply to me as I do not menstruate. Here's my question: since my parents raised me as a Jew, but didn't have me immersed in a mikvah, do I still need to "convert?" What does that entail? I am heartbroken as my Neshamah has been rising up the ladder to Hashem, only to fall down the rungs of the ladder. Todah, Shirah
From Shulchan Aruch (Y.D. 268:3) it's apparent that one who was born to a non-Jewish mother, would have to go through a giur process in front of 3 judges in order to become Jewish. This also applies to someone who kept mitzvot till now, as long as they never went through giur.
כָּל עִנְיְנֵי הַגֵּר, בֵּין לְהוֹדִיעוֹ הַמִּצְוֹת לְקַבְּלָם בֵּין הַמִּילָה בֵּין הַטְּבִילָה, צָרִיךְ שֶׁיִּהְיוּ בְּג' הַכְּשֵׁרִים לָדוּן. מִיהוּ דַּוְקָא לְכַתְּחִלָּה, אֲבָל בְּדִיעֲבַד אִם לֹא מָל אוֹ טָבַל אֶלָּא בִּפְנֵי ב' (אוֹ קְרוֹבִים) (הַגָּהוֹת מָרְדְּכַי) וּבַלַּיְלָה, אֲפִלּוּ לֹא טָבַל לְשֵׁם גֵּרוּת, אֶלָּא אִישׁ שֶׁטָּבַל לְקִרְיוֹ וְאִשָּׁה שֶׁטָּבְלָה לְנִדָּתָהּ, הָוֵי גֵּר וּמֻתָּר בְּיִשְׂרְאֵלִית, חוּץ מִקַּבָּלַת הַמִּצְוֹת שֶׁמְּעַכֶּבֶת אִם אֵינָהּ בַּיּוֹם וּבִשְׁלֹשָׁה. וּלְהָרִי''ף וּלְהָרַמְבַּ''ם, אֲפִלּוּ בְּדִיעֲבַד שֶׁטָּבַל אוֹ מָל בִּפְנֵי שְׁנַיִם אוֹ בַּלַּיְלָה, מְעַכֵּב, וְאָסוּר בְּיִשְׂרְאֵלִית, אֲבָל אִם נָשָׂא יִשְׂרְאֵלִית וְהוֹלִיד מִמֶּנָּהּ בֵּן, לֹא פָּסְלִינַן לֵיהּ.
All matters of the convert from making known to them the mitzvot, receiving them, the circumcision and the immersion, it must be with three who are fitting to judge, and during the day. But after the fact if he only was circumcised or immersed at night or in front of [the convert’s] relatives [which is invalid], or even if one did not dunk with the intention of conversion, rather a man who dunked for a seminal emission, or a woman who dunked for menstruation, they are still converts and he is permitted to [marry] an Israelite woman. So this all applies to the immersion and the circumcision but it does not apply to receiving the mitzvot, which prevents [conversion] unless it was during the day and in front of three [witnesses]. However, the Rif and the Rambam [say that] even after the fact [one who] immersed or was circumcised before two [witnesses] or at night prevents [conversion], and [marrying] an Israelite woman is forbidden. But, if he is married to an Israelite woman and she has borne him a son, we do not invalidate him [the son].
Important: if the above is something that applies to you in real life, make sure to discuss it with your rabbi instead of following advise from a stranger online.