Lmp was aug6.had sex on aug14 and 30 using withdrawal as control.no period up to now sept23.is it possible that I'm pregnant I'm 38 yrs old

More than possible.

It's very possible. The withdrawal method is not a reliable form of birth control. There are plenty of sperm in early fluids to get you pregnant.

If your period is at least 2 weeks late, try a pregnancy test using first morning urine.