When I meet new girls, I have no problem talking to them, being flirty and the best version of myself so far, so newly I attract a lot of girls (I don't do cold approaches because I'm only 17, I just keep eye contact, and fous on the conversation and flirt with them)

But when it's a girl I already know from when I was shy as fk and had no clue on how to act around girls (just a year before), I can't act like I act when I'm with girls I meet now. I am more shy, closed.

Is this a problem? How can I change this?

P.S: Sorry if any grammar/spelling mistake