If I stole and borrowed and didn’t pay back under thirteen am I still liable? I don’t really know how much I stole and and I wasn’t religious yet.
The halacha is that a child that caused damage or stole is not liable and does not have to pay it back even after he is an adult, and the person who the money was stolen from has no claim against him. However it is a good thing “l’tzeis yidei shomayim”- ( to fulfill even the heavenly want) to pay back something. (Technically it would be considered a pious act to return all of the money that was stolen, however in your situation that will not be possible, therefore do what you can, and after that H-shem will take care of the rest.)
Rambam Hlilchos Geneiva 1-8, Rema O:CH 343, Shvus Yackov 1-177, M:B Ibid 9.