My senior year in HS I did a internship for a semester at a local vet clinic bc I wanted to be a vet. LOVED IT. You will get to see things behind the scenes that you would never get to see otherwise. I got to see all the awesome fun things and also the sad or hard or nitty gritty things (i.e. euthanizations, amputations, dental work ewww).
You will also get to ask all the insiders lots of good questions like where to go to school, what internships to take advantage of, how to specialize, what their favorite/least favorite things about their jobs are, and get access to good journals or professional information. You probably won't get too much hands on experience because of legality issues but it would be a valuable experience regardless.
Just stick to your goals and make them a priority bc if I wasn't so swayed by all the social things at college (i.e. alcohol, other "substances", boys) I probably coulda been a vet by now. Let us know what you decide to do!
edit: I just want to add that if you DO decide to do it make sure that when you leave you show some token of your appreciation like a gift basket or lunch or at least a card. Four or five years after I graduated hs I took my cat to the same vet clinic for his first checkup and the vet did remember me and commented that I was the most involved and APPRECIATIVE intern that they've ever had. The small tokens really leave a lasting impression. Throughout graduate school it always surprised me the number of students that didn't give at least a card at the end of their clinical rotations. Its never too soon to start networking!