I'm 8'2 at "normal erection", reaching up to 9in at "full rage" and maybe had sex with 30ish girls and 4tgirls. I can swear you guys that, among them all, only ONE girl got physically unconfortable being penetrated.
She changed the position to cowgirl then rode me slowly until her pussy got stretched n wet enough; after that, we just continued normally.
It's super commom to see girls discussing/complaining in the internet about how they prefer medium sized dicks (usually 6' or 15cm) because big ones do hurt them (around 6'6 or 17cm), so I would say that, from this size on, the penetration might feel "different".
Although this doesn't seem to make sense at all, it has an obvious reason: the vastly majority of people can only "fuck", but not "have sex", if you know what I mean...
In men's case, it's very important to be the girl's guide to excitement (plus everything related to, u know), helping her vagina get hyper wet and fully elastic.
I can tell, from what ive experienced, that their vaginas may be more or less tight, but all of them will joyfully receive huge stuff (and ask for more) IF aroused and stimullated enough.
(it's really obvious that these stuff will vary from one to another, exceptions are never to be disconsidered).