I'm 19 years old and me and my boyfriend are sexually active. I'm now 9 days late for my period and I've never been late before, I'm on birthcontrol and have been for years. I took a test Sunday and it was negative. I'm not sure what's going on

Could be many things, including too early for test results. Of course you know that no birth control is 100 percent, so there is of course a chance.

If you are 9 days late, a HPT should give you a correct reading (as long as you follow the directions carefully)

Test again and if your period does not come by the time you are 14 days late, ask your doctor for a blood test.