What do I do to stop this lie?

I have mostly older friends. I am 15 and most of my friends are 17+. I was feeling pretty insecure about my age because people my age think I am boring but older people think I'm cool but I didn't like that my age sounded so young. So when my friends asked my age I said I was 16 and was born in 2008 but I was really born in 2009. It's been a while and I'm starting to feel really bad about lying to them. I want to stop this lie while also not looking stupid. I was thinking of just telling them one day that I always went by my conceived birthday because I personally don't believe in abortion so It would make sense for me and It would go with my beliefs and it would also explain why on legal stuff my birthday doesn't match what I told them. I don't know if I should "stop" the lie with another lie though. Does anyone know what I should do? Yes I know this was so stupid and immature to start. I get it and I have come to that realization. I just want helpful answers please
What do I do to stop this lie?
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