This is the beginning.
That is the most important part of this. Son's college coach emphasized it a lot, and it especially hit home because a kid who had committed as a sophomore in HS had just announced that he was withdrawing his commitment after he and coaches mutually agreed it was no longer a good fit. I don't know this, but based on what we heard, I interpreted as code for "he stopped working."
Other kids who committed early came into the program and left within a year or two. It felt like they expected to rest on their laurels and din't realize they still had to work. So remember, a commitment to any school is just the beginning. That's when the hard work starts.
As for the scholarship — my son is at a P5 and they offered him a specific percentage. Freshman year, he got that. Sophomore year, they asked if we wanted to increase one year, decrease the next. It balanced their numbers better and worked fine for us so we did it. Over four years, it will work out the same amount.
Son followed pretty much the order Smitty says, although some of the people we had worked with most closely, and who I think were instrumental in his recruitment, knew what he planned to do — it wasn't hard when one of our last steps was to ask them — "in your professional opinion, does son have what it takes to succeed and play at this school?" When they said yes, we all kind of knew where it was going.