First of all, be happy that you are being offered the chance to apply for a clearance. They are worth substantial amounts of extra salary in the DC area job marketplace. Also, you are filling out the form at a young age and presumably you have not had any significant life events that would hurt your chances.

The federal government officially claims travel is broadening, which it is, and officially encourages clearance holders to travel. The reality is that you could receive some amount of hassle for travelling of which having to fill out forms could be only the beginning. Depending on what country, what government agency, and what clearance level you have, you could have to report foreign travel after the fact, or even get permission before the fact.

Ask your Facility Security Officer about "mileage runs" and see what he or she says and get back to us.