Don't know where you are but in this drought it will be quite common that the garlic cloves are not as big as in other years. Now they are maturing and don't need much moisture, but a couple of months ago it would have been beneficial for clove size.
Don't worry about garlic going to seed. It actually does not go to seed in a conventional way, but it will flower and on the flower stalk, which is called a 'scape', garlic bulbils will develop. These can be as small as a corn of rice or smaller or they can be about half the size of a clove, depending on variety. They are just as good to eat as garlic cloves.
This flowering is fascinating to watch. All hardneck garlics flower. Softneck varieties don't, but they can develop bulbils in the neck of the plant as a stress response. When hardneck garlics start sending up scapes, these are usually tightly coiled and then uncoil and straighten out. Yes the flowering does take away a bit of energy from the bulb development and this is why the usual advice is to cut them off. But it makes not a lot of difference. Garlic scapes are very delicious if you harvest them before they harden, at the coiled stage is best. Nice chopped up for a mild 'green garlic' flavour.
My hardneck garlics have started sending up scapes too.