Their will be peer pressure on both sides so she doesn't need the stress of her parents not liking him to add on to it.
Be as open to the subject as you can for then she may feel like you understand or will at least let her try to handle herself to a point.
Personally, I think dating in high school isn't all bad (nerve-wrecking for the parents, yes, but not all bad).
They're young and gaining experience in the world, learning about how people and relationships work.
Spend time getting to know him and see how they interact.
Share your concerns with your daughter and pay attention to you intuition if you feel something wrong is happening and always make sure that your daughter knows she can come to you to talk about anything with no judgement. Get to know him and figure out their feelings for each other.
Although it didnt work out my relationship lasted three years.
The best thing you can do in this situation is show support.
You cannot make this decision for her, she will just rebel against you and continue to see him.