never engage, not even vaguely. they're just looking for a reaction. it doesn't matter how epically you dunk on them in public, or how thoughtfully crafted your point-by-point rebuttal is, it's just going to encourage them.
maintain good internet hygiene. be mindful of revealing personally identifying information in public. no one is ever owed your exact age, for instance.
if you get stressed out enough about a particularly intense situation, log off for a while. this is another method of disengaging.
in my experience, most people prone to harassment will give up and find a more satisfying target fairly quickly. there is a small outlier that might be deranged enough to harbor a lasting, personal vendetta against you--but there isn't a single thing you can do about that, short of vanishing out of public spaces entirely.
as an aside, being a creator on the internet is a delicate balancing act between vulnerability and safety. people are often drawn to sincerity, to clarity of vision and earnest intention. but expressing too much of this consistently, for many, can range from exhausting to downright dangerous.
the internet is inherently untamable. no matter how much money people dump into wrangling it into a more appealing shape, the veil of anonymity will always enable many people to indulge in cruelty.
it's up to you to decide whether you feel the risk is worth it. at this time, i think it is.