If i'd never had sex before, could it be an std/sti?

Almost certainly not: Almost certainly not -- but it depends on what you mean by "never had sex". STDs are almost entirely transmitted by direct genital-genital, genital-anal, or genital-oral contact. If these have never happened, almost certainly you have no STD. However, there are rare exceptions, such as potential rare transmission by hand-genital contact. A baby born to an infected mom can catch certain STDs.