It can make pedos attracted to you even though they know you are 20. How. to react to that is of course up to you. But it is something to be aware of.
I haven't looked for that comm and won't, but it sounds intended to attract viewers with pedo tendencies. Whether that's a safe outlet or a red flag, idk. I do know that Reddit and other sites go apeshit banning even erotic fiction with underage characters. I have heard they do that not from concern that the fiction could be illegal per se, but rather that they don't want to create a pedo magnet that could then bring the pedos into contact with actual underage users.
OTOH, I know that AO3 chose not to have such a rule. IDK if that has led to any bad stuff in real life. I hope not, of course.