When you say "work out" you mean get married and long term? That rarely happens with HS relationships which is why there's a special term for it- high school sweethearts. Most people don't end up marrying the girl/boy they dated in HS.
I don't want to discourage you, but I don't want to lie to you either. You may well grow apart. She'll still be at HS while you're at college. One or the other of you might get frustrated not being able to spend time with each other. You might have different interests.
Depending on where you live, consent plays a role in this as well. Correct me if I'm wrong, but once you turn 18 you will not be able to engage in sexual activity until she is older. I assume she's about 14-15 currently. If the age of consent is 16 that might not be an issue if she turns 16 when you turn 18. But if it is, that's something else to keep in mind.
I say go for it. There are all sorts of stories where two people who were unlikely to end up together- for whatever reason- ended up together. I don't know how it'll work out and nobody else here does either. I don't know you or her. You may be very mature well rounded people and this might work great.
Massive age difference, different points in life (about to graduate, other still in high school), different priorities (one is entering the adult world: workforce or college. Other worried about SATs and social life in high school), maturity levels are different, goals are different, people change when they meet new people or are able to try different and new things. The relationship wouldn't last too long.
In theory, it could work out, but in practicality, no relationship a freshman is in is likely to last. When my daughter was a freshman, she dated a few seniors. I don't think any of them lasted a month.
I always found it pretty questionable. A 3-4 year age difference isn't much in the adult world, but in HS, 3-4 years means the world of a difference.
I don't know how it is for you, but in my school, the freshman look like barely developed pre-teens, and the seniors look like young adults. There is a massive jump in puberty and overall maturity over the course of 4 years of high school.
Plus, if you are a senior, and you go off to college next year - you and your girlfriend will be seperated for three whole years. You will be an adult who has to study and work hard, with barely any time on your schedule, and she will be enjoying her childhood without a care in the world, and she won't even be able to drive yet.
You two will not only be seperated by distance, but you will be at completely different phases in your life. It just isn't practical in my opinion. Best avoided, if possible.