As a child I received birthday money every year (I don't remember if I gave maaser at the time), my Parents put it in an interest bearing bond and when I turned 18 it matured and I was given $13,000. My Parents said the purpose of this money was to save it and help support myself and my husband when I get married. Do I have to give maaser on it now? Thank you!
See the 2nd paragraph, here, based on primarily sources from Choshen Mishpat:
Money that is given as a gift by parents or friends for a specific purpose, e.g. to purchase a car or go on a vacation, is not considered income, and Maaser need not be separated from it. (based on Choshen Mishpat 241:5)
Your parents saved it for a specific purpose, and when they gave it to you, they stipulated that same purpose. This is different than if they gave you $13,000 and said that you may do what you wish with it.
It is unclear to me if you have to give ma'aser post-fact, if you end up using it not for the purpose that it was given to go on a one-time pleasure cruise.
Also, within this caveat, I infer that you can't even touch the money until you get married! What happens if you remain single?
BTW - if you are single, I may have some nice boys that you may be interested to meet, if you are "in the parsha" :-)