Before I turned 3 but not sure of the exact age - going to see my grandma at the swimming pool where she worked as a receptionist, and also being at pre-school and cutting myself on the sellotape dispenser.
Also a lot of memories from 3-4, mostly spending loads of time with my dad, especially when we went to the theatre and saw Swan Lake. Not exactly happy memories anymore, only found out last year that the reason I was spending so much time with him was because my mum was in hospital with my grandad... But up until then they were very fondly remembered. Also remember finding out that he'd died, which was about a month after my 4th birthday (and getting really confused because she'd worded it as "He's gone", so for about 5 years I genuinely believed that dying meant you evaporated away.)
It's funny how detailed some memories are - I remember the decoration in the theatre for the ballet and what ice-cream I had in the interval (chocolate) and sitting on the flipped-up chair so I could see the stage, but I don't remember my first day at school.