There is absolutely no way to know how your foreskin would have been. If you dad was uncut, you might have some idea based on his, but even that is 50/50 since you also have some of your mother's genes. (yes, mother's genes also help shape your most manly posession: your penis)
The only thing you can do is to look ata wide variety of uncircumcised males in their truly flaccid state and tell yourself you could have had any one of them, ugly, long, short etc.