I dont think thats out of the norm at all. When i was living with my family id only use a towel 2-3 times max.

That said im currently living with my partner and we go through ~3 towels a week. However since we don't pay too much attention we might end up both using the same towel most of the week before realising how grim its gotten. Mostly this is down to us only having a few towels and being too lazy to wash them more than once a week.