Yes, it's fine - no one will stop you. Once you touch the food and bring it back to your table, whatever you don't eat will go in the garbage anyway. Bring a bag or zip lock to keep your fruit clean if you'd like.
The fruit costs more than it should - about $1.50-2 for a whole fruit and 3.50-4 for a cup of fruit salad. That can be a snack on the dining plan.
Thank you. I will get fruits from buffet and get dry goods for snacks.