Ever since i had my first time, my vaginal opening feels different, more bumpy. before i had sex and inserted a finger it felt like there was a ring which i could tense up around my finger, now it gone. would someone else be able to tell i had sex?

There are several activities which may cause rupture of the hymenal ring, and may be thereafter a reason a self exam or one by a prospective partner may not reflect the hymenal ring as present. If the physical intimacy in a relationship is dependent on this sign of "virginity", it is probably best to discuss this prior to the relationship reaching this point.