Early ovulation

Natalie
My cycle started 17 days ago and my typical length is 35 days (boo!). I've been cramping a little and experiencing some symptoms of ovulation so thought I'd take a test. It was positive. Usually I ovulate at around day 25. 
How common is it to ovulate early?
I must have ovulated early earlier in the year too, I got a BFP in March about a week before my period was due and not long after my prediction said I was due to ovulate but unfortunately I suffered an early miscarriage.