At your age a test booster is prefectly safe. But to be completely honest, anything Tribulus is a a serious hit or miss. It literally does nothing for most people.
Not to mention their are better products out there to helps boost natural levels of the hormone.
Try Activate Xtreme by Designer Supplements.
At your age you'd be fine to start doing Prohormones and Gear so a Test booster won't hurt you and actually could be beneficial.
I'd just find a better alternative than a Tribulus based product.
Also what is your goal. Higher Testosterone levels have a variety of benefits but what are you looking to do?