So, if I understand this correctly, you want to know if having sexual intercourse for the first time on the day before your period is due could delay the onset of your period?

Stress or anxiety can delay your period (or bring it forward), so if you found the experience stressful, it could do by a few days or so. It is, of course, possible to get pregnant the first time you have sex, if protection is not used. This is much less likely at the end of the menstrual cycle, i.E. Just before the period, but it is still possible. So, in that sense, your period could end up being delayed by 9 months.

The second part of your question doesn't really make any sense. There is nothing to "heal" after becoming sexually active. The hymen may break the first time one has sex, hence some bleeding, but many women will already have ruptured this through sport or physical activity before having sex for the first time. In any case, this does not "heal" in any meaningful way.