I will assume that you would mean to enlist in the guard unit that you would eventually like to fly for. If that is the case then yes, that can be of benefit to show your interest in the unit and be an enlisted member while going through college. When you finish your BA or BS you can then apply within the unit for a pilot/offer spot. There is no guarantee though. If you don't get one you could always apply elsewhere (other guard units or active duty) or quit when your service is up.