Tetracycline family of drugs affect growth after age 8?

I know it states not to take tetracycline before age 8 because of in can affect growth.  I am 13 and have been perscribed doxycycline for my acne - 150mg/day.  I am still hoping to grow at least an inch more, and care more about attaining my real height than my acne.  I want my acne better, but not if it means I'll be even a cm shorter!  When I asked the doctor about this at my visit, he laughed and said his kids would like to be 5 3.5 like I am, since he and his wife are both short.  This didn't really answer my questions, and I don't want to start taking it until I know if it can affect my height.  I have only had my period for a year, and have even grown 1/2" in the last month.  I look forward to getting an honest answer from someone!  Thank you!