Sexual arousal for men is often characterized by higher testosterone levels, which peaks in your 20s, and a higher sex drive does as well. At the same time, you may also be nervous about intimate relations because of your lack of experience. It may be possible that part of the reported erection dysfunction of up to 8% of men in their 20s is because of this issue (ED). You can still have satisfying sex as you age if you’re in excellent health.