What is normal time duration?

i am 21yrs,i wants to know what is normal time?i tried 3 time,but i fail to ejuculate during ..due to loose at the time of ..i used condom every time,i did not try without condom.may b 1st time it be bit scared but from 18-21 m not sucessful..how to know that have i any problem or just mental situatuion.. during is good..and i have normal size 7inch & grith 2-3inch.i do exercise daily and i do bodybuiling a bit,i dont take any suplements aand i dont have any medical problem yet...what to do