I don't know about the fit bc I have no idea what size you are and maybe the seat is too low.

As for upgrades, don't worry about it until you notice something not working. I've been doing 15 to 40 mile MTB trails and training for a century with some 60 mile road rides and I'm completely happy with the stock bike. I put on a different saddle but that's it. I'll upgrade later if I see I'm at a disadvantage.

Too much emphasis on bikes and components and not enough on the rider in my opinion. Go ride, you will love it.