Congrats on your first sexual encounter. Oral sex, protected oral sex. So, with regards to HIV, unprotected or protected oral sex is zero risk. The only risks for hiv are to have unprotected vaginal or anal sex or to share IV needles to inject drugs. Air and saliva inactivate the virus. Remember that. That's the only way you'd have any risk for hiv. All other std's are low risk for unprotected oral and they don't even recommend testing unless you get identifiable symptoms. Using a condom during sex makes it very unlikely you'd get an std as you had a barrier. I would not be worried.