Don't be anxious! Undergrad is fun. Try to enjoy it for what it is. Yes, you have a goal in mind, but you have a few years - try to have a good time.
For now, just do well in your classes. Once you get settled in and you know how you will do with coursework etc., you can look into some opportunities for shadowing at local clinics, getting some laboratory experience, things like that. It would be fine to wait until spring semester has started to even worry about it - unless an opportunity falls into your lap.
Is there a pre-vet club at your uni? Joining that would be useful. If you are near a vet school, you can always set up a meeting with someone to just discuss your overall course plan and timeline. But again, no rush - you need to adjust to college life, make some friends, have some fun, and work on the classes you're taking now.
Hanging out here and reading posts will go a long way in helping you prepare and giving you ideas for experience. Just read things as they pop up, and in 6 months you'll know pretty well how the whole application process works and what sorts of classes most schools require you to take. Then you can post here and there, ask some questions, make some friends, maybe play some WW... it's all good.