I don't think an A1c of 6.8% is "good" it is not bad, but could be better.
We all have to accept the best results we can manage and we are all different.
I wouldn't eat cheesecake, it is high in carbs and once you start eating small amounts then it's a slippery slope.
There are lots of low carb alternatives that you can eat. But you have to want to.
So no more cheesecake or we will "send the lads" round.
Try jelly (sugarfree) Greek yoghurt or Fresh Cream add blueberries to the jelly (I like blackcurant flavour) or a fresh fruit salad.
H