At 10, kids are beginning to be told about the birds and the bees in enough detail to get the idea of what happens, and they sometimes dream about it because they are thinking about what they have been told.
To try to sort out whether it was based on a real-life suppressed experience or not, you might think about whether the sex you had in the dream was actually realistic. (You said the dream was "very detailed," but has subsequent experience proved that it was correct?) Even a 10-year-old who is getting adequate sex education would have places in a dream about sex that would be wrong, or have pieces missing, or in some way the dream would be incorrect to true-life experience.
Someone who finds the thought of sex a little peculiar or distressing at 10 (which is not unusual at that age!) might have a dream that pins itself on a certain guy without actually having had it occur.
It seems like if you had had sex at an earlier age than 10, you would have known it at 10 when you had the dream. Also, if the dream was a rehash of a real experience, it would have contained dismay or fear or anxiety. Kids who are abused often will report on random details that don't stick out in the minds of adults, such as they will often talk about how much liquid there suddenly was and this was a surprise, like they had wet themselves. Details like that would have stuck in your mind if you were abused, and would have shown up in the dream. You don't mention that the dream involved you being fearful or confused, and one would think that if earlier you had been molested, those emotions would be at the forefront in the dream.
Regarding the body-image issues and shyness around puberty and all, it's possible that the dream and the self-consciousness all came from the entire topic of dealing with growth, puberty and sexuality, not from one incident that perhaps you have buried. It might all have been one package, your own way of coping with sexuality and being a sexual adult. (Here you were going along being a kid and having fun, and suddenly you have this different body and men are reacting to it and it's a whole 'nother thing.) I'm not saying that someone close to you didn't react to you in a way that made you feel self-conscious, but am suggesting that it's as likely the dream came from your worldview about sexuality, instead of your worldview about sexuality coming from some actual sexual event (now a suppressed memory) that was reflected in the dream.