Hmm, I have to ask two things -
why are you delaying "sex" simply because your foreskin is too tight, and presuming (as I rather suspect) that by "sex", you actually mean vaginal intercourse, then what sort of sexual activities have you
already been pursuing?
In regard to the first, the question is - as you might see if you take a good deep read back through this discussion board - why do you connect being able to retract your foreskin with intercourse? If anything, a foreskin that becomes painful if it is pulled back too hard, is a somewhat useful warning that you are at that point, doing something badly
wrong, which will make the experience equally unpleasant for your lady-friend (and for just
what could be wrong - well, I have mentioned that in many recent discussion threads).
Perhaps a more important point may be that (unless the young lady in question is using a "
guaranteed" contraception such as Implanon® and not just "the pill"), then you clearly
will need to be using a condom by the time your genitals touch because you clearly do not wish even the slightest risk of pregnancy - which
is a significant risk in terms of the consequences.
As to my other question, I would hope you do not see intercourse as an "end" in itself. It is actually merely
one part - and sometimes not a big part - of "sex", and I venture to suggest that unless you have spent
some considerable time (what might that be? - well, months at least) exploring all the
other aspects, then (both of) you will be in for quite a disappointment.
One might also be inclined to the opinion that if you do not understand these details, then you perhaps really are too young to be having intercourse.