You mean you approach a girl, hit on her/show some intent, and she looks disgusted and tells you that you are too old?
There's all kinds of PUA theory you could implement, but it's all just marketing/theoretical BS tbh; Most common advice is to consider it a 'test' and then agree and amplify - 'yeah, i'm old enough to be your grandad. Anyway, lets go out tomorrow' kind of thing.
It doesn't work though lol.
Not everything is a 'test'. (in fact, girls 'test' you way way less than PUA's want you to believe! They often don't want to risk losing you if they are actually attracted!) I've heard deluded PUA's say everything is a test to the point there's nothing a girl could say to them that they would take as a 'no'. They'd consider a restraining order a 'sh1t test'
If a girl isn't into you (she thinks you are too old and ugly or whatever e.g she's simply not sexually ATTRACTED to you or interested in that way) then there's nothing you can do about that.
Say goodbye and Move on to the next girl.
This really isn't a game of 'skill' as such. Even the best PUA's can't negotiate attraction and turn 'no's into 'yes's', as we can see from infields.
It's a numbers game.
Choose your battles