Don't put any information about yourself on the internet that you're not comfortable with having someone who fucking hates you and wants to destroy your life having. Once it's out there, it's out there forever. You're a lot easier to doxx than you think. You don't have to give anyone any information that you don't want them to have. Don't let yourself be pressured into putting information about yourself on the internet. You don't actually need to put ANYTHING about yourself in your bio at all. Other people's boundaries do not mean you need to give away your information if you don't want to. They can choose not to interact with you if you don't disclose your age but that's their choice and doesn't say a damn thing about you.
I don't know if any of you have been doxxed. I have. Multiple times. I've had information about restraining orders I filed for my safety posted online, I had information about charges I filed against an ex posted. I had information about my job at the time posted and people discussing whether they should contact my boss and tell him I was lying about being domestically abused. (Uh, I wasn't. I was afraid for my life. Dude was violent and suicidal and had access to firearms.) I had people contact my rabbi and try to fuck up my family's relationship with our old synagogue. (It didn't work, but it was really shitty and a really stressful time.)
I've had people figure out where I was from a picture of flowers I posted. I've had people trying to track me so they could report me to my abusive ex.
Your information online is yours to do with as you want, and you should protect yourself. Anyone who pressures you to reveal anything about yourself - your age, your location, your full name - is out of bounds and does not have your best interests in mind.
Don't put a goddamned thing in your bio unless YOU want to do it. You don't owe strangers on the internet fuck all about yourself.
Other people get to set boundaries for themselves, not for you.