[FONT=""][COLOR=""][SIZE=""]TL;DR:
I thought my friend was 19, but is actually 23. I need help on how to confront them about it. I don't plan on being friends with them anymore, I just want to give them closure because we've been friends for 3 years(I don't want them to wonder about why I would suddenly ghost them.)

Context:
3 years ago I was in an online friend group, I was 13. We were all teenagers, I first met my friend(gonna call them Fire), they had told the group they were 17, but because I was in a group with a couple of other teenagers I wasn't too uncomfortable. Basically the friend group fell apart, and I remained friends with Fire. We've been friends for 3 years, and they have told me they were 17 still. I found out they were 23 from an account on one of their other social medias. I am really uncomfortable, because they were 20 when I was 13. How do I confront them and give them closure?

(note: they have never ever done anything inappropriate with me, we are just friends)[/size][/color][/font]