Congratulations of getting into grad school! I would say definitely go for it, because Ph.D. will be with you for the lifetime.
As far as it being in person, there is such a thing as "hybrid classes" where the students can either be there in person or watch them on zoom. And, besides, not all classes are like that either. In fact, in my school, they "say" its "hybrid" yet most classes are by zoom. They only say its hybrid because some minority of classes are. At least in my school, it is split between strictly remote classes (the majority of them) and hybrid classes (the minority of them). There are NO classes that would only have in-person option. They would never do that during covid. If one crazy professor decides to do that (which would never happen), you can just take some other class instead.
In any case, please don't throw your career down the drain due to covid. I am sure they have thought about the safety precautions. They are all on the same boat.