As a general rule, at the point you start your pension saving, you should be saving half your age as a contribution. So start at 20... 10%, start at 30... 15% etc. as it stands, with what you are doing, you are well on your way to a healthy retirement pot.
I get 20% a year into mine and I'm hopeful of a sensible pot when I retire.
If you are concerned, I'd genuinely speak to a Financial Advisor. They can be worth their weight in gold.