My blueberries were smaller this year?
Blueberries have always been larger than this year.
Certified GKH Gardening Expert
You didn't mention whether you're growing your berries in a garden or in pots. It is thought that if you plant a few different varieties rather than one kind, the berries are likely to increase in size.
This article contains quite a bit of information about properly caring for your blueberries: