No need to worry. Oral sex will not lead to HIV transmission. The only risks for HIV are to have unprotected vaginal or anal sex or share IV drug (injectable) needles. Air and saliva both inactivate the virus. So, even with her braces, even if you had/got a scratch or blood on your penis from her mouth, you would not get HIV from this. NO RISK>
You did not have any risk for HIV, and you do not need to test. The only risks for HIV in adults are:
1) Having unprotected anal or vaginal sex, or
2) sharing intravenous needles.
There is no other activity you could think of, including the event you mentioned, that would put you at risk for HIV.