A failure to appear will likely result in a warrant from the Traffic Court. Your best move is to go to the Traffic Court and have them recall the warrant, remove the Failure to Appear and you take care of the Speeding ticket.
You can be arrested on the arrest warrant for failure to appear, but it is unlikely that you will go to jail.
Sometimes clients will say that they received a speeding ticket when it was actually a reckless driving by speed charge. In Virginia, reckless by speed is a first class misdemeanor. If the speed was high enough, jail time can result.
Failure to appear is also a first class misdemeanor. The fact that you were only 16 will probably help you.
On the other hand, if this is just an issue of not paying a fine there should not be much of a chance of jail time - especially if you are ready to pay the fine off.
Call a local traffic attorney for a free consultation.