I think you are doing well.

There are some riders who are faster than others. I am not a fast rider; I went on a 50 mile ride the other day and between stop signs, hills, and my general wussiness, I averaged 13.6 mph! I've been riding a lot longer than DH and he puts me to shame in maintaining a high mph.

I know you'll read it other places but everyone progresses at their own rate and everyone has a different riding style. I'm not fast and fast short rides kill me but longer slow rides don't.

You haven't been riding long enough to judge yourself Just have fun with it, don't have unrealistic expectations, and don't try to live up to what other people think you should be. It should be enjoyable instead of a source of pressure.