Dude, take some time off, travel, have a crappy retail job for awhile and BE 19! There is no reason to press the fast forward button on higher ed if you got through undergrad that quickly. Granted, having a degree that doesn't automatically put you into a pool of candidates for immediate hire is scary....and not easy to transition to (I majored in dance, so, I can completely understand). However, you are considering a profession that values life experience and personal growth (among other, quantifiable things, like grades, GRE scores, and specific gpas). So you should go out, and have some life experience and get some of that personal growth.
I am a non-traditional PT student. I had a dance career first, with multiple retail and food service side jobs, and then once my dreams were sufficiently crushed by the recession and general burn-out due to my unpaid status, I switched to massage therapy. Massage then brought all those dreams I set aside to be a PT to the forefront, and I dove in headfirst and got into 2/2 fabulous schools my first round of applying (after 2 years of post bacc, let's be honest here).
My class is divided, probably 2/3 of people came directly from undergrad and 1/3 of us had some other life trajectory that brought us to PT school. Everyone is amazing, and has a lot to offer, but the people who had real-world experience outside of the warm cocoon of college already have experience that directly affects their clinical reasoning, interaction with patients and teachers, and other students in a very good way. I think adcoms don't specifically look for people who have had more life experience when they apply, but it never hurts.
Bottom line: PT school is hard. It's draining. The amount of content you NEED TO KNOW is ridiculous. If there is any opportunity to have a break and be a person and not a Kendall-toting goni zombie for 3 years, you should take it. PT school will still be there when you are ready. Also, if you aren't yet 21, then you can't have the post-first-anatomy-test bender (legally) and who wants to miss out on the celebratory tequila shots while talking about the pathway and axonal components of the ulnar nerve?