Oz a virgin?

guess the movie tried to sell he was on the shy side (?) if I remember correctly.

suspicious either way

Sometimes the jock/popular guys can be shy and not great with women even though they are with sports and such. I don't think most guys that age are as sex mad as some.

He was a bit shy and also socially inept, see the car scene with the girl.

The car scene made it pretty clear that he didn't have much experience in even talking to girls, let alone having a girlfriend. Partially out of shyness, but also just not really taking the time to learn how. After the college girl gave him some advice, he actually took it to heart, and within a month was banging Mena Suvari.