<human>: Can you give me the gist of the text in a nutshell?

Basically my friend has admitted to wanting to move to a relationship and I like him as well but his age is bothering me.

To brief it down majority of my friends are a good chunk older than me like 5-9 years and I'm so used to being around them that I tend to forget that I'm also not their age and keep thinking of him as super young and just "a little youngin" as if we have a huge age gap between us. Mentally I see him as 19 but can't see myself as 20.

I know realistically its a year, not a huge deal in any other situation but because I don't think of it as 19 & 20 it's preventing me from seeing him as only a year younger than me. I am attracted to him and would go for it, but I'd be much more willing of he was older. In my previous relationships I've always been the younger one so I don't understand why him being younger than me is making me hesitant.
<bot>: Friend wants to date me, I keep picturing him as way younger than me as a result of letting myself think that I'm way older than I actually am.