Hello and welcome to healthcaremagic
Rather than speculating about your
HIV status, first and foremost, you must get yourself tested for HIV, since the sexual contact was 4 years back and therefore you are well past the window period for detection of HIV (3 months).
Therefore, testing for HIV
antibodies would tell you your exact status.
However, coming back to your query, the risk from insertive unprotected vaginal sex with an HIV positive female is about 0.04%. However, the presence of cuts, abrasions, std's, bleeding etc are biological factors that increase the risk.
It is important to emphasize that a person could become infected from having unprotected sex once or a person could have unprotected sex many times and not become infected, regardless of how low or high the risk per exposure is.
hope this helps
regards