As A Nsfw Artist Am I Legally Allowed To Ask For An Id Or Some Form Of Confirmation For Nsfw Commissions?

I am a not safe for work artist and plan on taking commission in the future, I already feel sketchy at times posting my art online our of fear of someone underage comming across it let alone the possibility of a minor attempting to commission me. I've seen some use the honnor system or use some form of acknowledgment in terms of service for their commissions that “if you proceed you confirm you're over the age of eighteen” I intend to use cashapp to accept payment wich requires you to be eighteen (though they can have an account wirh a guardian’s permission) but im looking for other forms of confirmation as a failsafe due to the possible legal and outright moral consequence of selling to someone underage I've thought about PayPal but I would prefer to keep my identity private