Should I be worried?

The Last time I mated Sage ( my 15 month old blue cream perisian ) was back on Easter weekend. She didnt have any kittens. She has not come back in heat since. This was not her first heat either she had 2 others before this matting. I have read that females should come into heat every 3 or so weeks during the summer. Should I be worried ?

I myself might be a bit worried. Perhaps a call to the vet about it before going in.

Nah don't be worried some queens call one year and then don't call the next. Some may never call at all!