it really varies. in probably 90% of cases, the answer is a hard no.
first, you have to think about where you were when you were 19. what were your ambitions and goals? what did you want in a partner? what was your mental state like? because the majority of us, had no good answers to those questions. at 19, we're discovering the independent adult world for the first time. and you're 10 whole years ahead of this person. at 29, you should have your life mapped out to some extent, where you live, who you are, what your long term goals are, and if you don't, you probably aren't very mature - and that's probably why you're even open to the idea of dating a teenager to begin with. because if you had those things, you wouldn't be interested at all in someone who's just learning to be an adult.
while it's possible for someone to be mature at 19, that's just for their time - maybe they've experienced more or are on a good track in life. that's awesome, but you still have 11 years of experience in the adult world, and they barely have 1. they might not know what a real, loving, committed relationship requires or entails.
however, you're both still technically adults, so, have at it. just ask yourself, why would you want to date someone who's 19? i'll bet you 9 times out of 10, the answer is "i'm lonely" or "i just want to have coitus" and there's nothing wrong with that, it's just important you be honest with yourself so you don't end up with a broken heart. it is very possible that the age difference can be ignored, you each find what you want in each other and be happy. it just isn't that likely. remember - who you were at 19 vs 29, is likely very different.
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If Jesus died for my sins, then I should sin as much as possible, so he didn't die for nothing.