I'm a girl with genital herpes. as long as my partner use a condom and i take my medicine will it be ok to have sex?

Not always: If you have herpes lesions present, you are infectious. A condom will not prevent it because herpes lesions is usually on the skin. Herpes is spread via skin to skin contact, not semen or vaginal fluid. Even if you don't see or feel lesions, you may still have them and could infect your partner. Your risk of that is much lower though.

Herpes Transmission: Vaccines that can prevent a genital herpes infection are not currently available. But research has shown that an hsv-infected person in a heterosexual, single-partner (monogamous) relationship who takes the antiviral medicine valacyclovir daily to prevent recurrent outbreaks also reduces the risk of infecting his or her partner. The addition of a condom further decreases the risk of transmission.