Possible easy answers
There may be possible and easy answers to your question. You could go onto one of the on-line chart calculation sites and run a chart for 8:00, 8:15 and 8:30 pm. While the charts will be very similar, the major difference will be in the MC and ASC angles. You will be looking to see if there is a planet at/near one of those angles. If so, ask yourself if you express that planet's symbolism. If you do, use that associated time. If you don't, then one of the other times may be more appropriate.
Now, if you have moved some distance from your birth place -- now, or when you moved to North Africa -- you could run a chart for those locations and for each of the three times. Again you would be looking for a planet near the ASC or MC angles. If so, was your experience in that location symbolic of that planet for that time of birth? This is a lot of detective work but may be the only way of telling for sure what your approximate birth time is. Dave