Honestly, you don't really need the test unless you will be working as a pharmacy technician during your first year of pharmacy school. In Texas, you cannot obtain a Pharmacy Intern license until the end of your P1 year (though in some states, you can obtain a Pharmacy Intern license immediately upon pharmacy school acceptance). However, once you've completed your P1 year, you can sign up for a Pharmacy Intern license, and that will double as both a pharmacy intern license (kinda obvious) in addition to being a pharmacy technician license.
I suppose you could put it on your resume (although honestly, you might be better off listing extracurricular, volunteer work, and community involvement instead). Being licensed by the PTCB will only look good to stores looking to hire a pharmacy technician. For internships and residencies, actual experience (as measured by hours) will be what matters.
The PTCB test is, however, pretty easy, though I am skeptical of its worth to you. I would spend some time to look over procedures and legalities in a review book if you can. The drug names may be difficult but won't be a significant part of the exam. If you can do proportions and basic algebra, the math should be easy too.
--Garfield3d