Is a 7/8 weight fly rod and reel appropriate for what I am using it for?

I have been fly fishing for a little over a year now, and I bought a scientific anglers b rod and reel. It is a 7/8 weight reel and rod. I use it on the main branch and the north branch of the ausable river in the northern part of the lower peninsula of michigan for trout fishing. I use the normal flies for that area, and normally only fish between dawn and dusk. I have been catching small to medium sized fish, and the rod casts well, and it is alright for handling fish that I am catching. I was wondering if I should buy a new rod and reel combo, with a lower weight when I can afford one (I am wanting to learn how to tie flies, and I was saving for a kit), but I am only 15, and I just started fishing. Should I get a lower weight rod, or wait?