Hi I did an ovulation test on day 10 of my cycle was positive so when should I have intercourse to fall pregnant?

Days 10-12. The day of the positive test, and the next two days are your most fertile days. About 15-16 days after the positive test you should either have a period or be pregnant. If you're not sure if you're pregnant, or you have spotting instead of a 'normal period', get a blood pregnancy test. Best wishes. If you're really 42 i recommend seeing a fertility dr soon for fertility testing as age is a factor.