Didn't have undescend testicular at birth or in child but when i was 20 i feel some days my one testicle is in abdomen but not always,is it possible?

Cremasteric reflex: One testicle usually is lower than the other, also, when you are frightened, or exposed ro cold, a reflex called the cremasteric reflex causrs tour scrotum to contract and the testicles are retracted up towards the abdomen

Yes: It is possible for the testicle to retract up to an area in the lower abdomen call the inguinal ring / inguinal canal. An exaggerated reflex called cremasteric reflex often causes this response. At age 24 years however, I will recommend a consult with a urologist to help differentiate this from true undescended testicle and provide you with proper information on testicular health. Take care.