It doesn't seem unusual to me. But, I have the same problem with my only child.
Ds is 2.2 and can count to 26 (mummys age!), including knowing whether he has 2/3/4/5 cars etc if asked. He's been able to do this for a few months. He can also read numbers 0-10 which he picked up about 2 months ago (so around 2.0).
Since June last year he's known all letters of the alphabet, what letter words begin with and the phonics (sounds) to match. He'd have been about 20 months when he grasped it properly - ie using it in every day situations. He's starting to recognise written letters and currently knows about 8 I think.
He's known colours since 17 months and now knows a good chunk of shapes.
Everyone who meets him is amazed by him. He was rushed into hospital a couple of nights ago with croup (didn't know at the time and is perfectly fine after some meds) and had the ambulance crew in complete amazement with him and slowly gained an audience of nurses who were gobsmacked.
As I said, he's my first and to me, he's 'normal'. It's only been more recently when attending more activity sessions aimed at toddlers that I see he's well ahead of all we meet his age and all 3 year olds I come across and more and more people are commenting on him now. A friend of mine who is a nursery worker came round a few weeks ago. I've not seen her for years and she couldn't believe how much he knew (she even picked up on things I hadn't even spotted such as turning pages correctly in a book) and said at her nursery they often send children from the nursery off to school not knowing as much as he does. So, that got my attention a bit!
However, as bright as he is now, I don't take it too seriously as he's still so young. He could slow down and become uninterested and be relatively average by the time he attends school. I think they're too young at this age to be judging it and deciding how well they'll do at school.