It is hard to tell home old hey are by size. Yours are adults though as they have their pads, are amplexing, and calling. I have a male that is a year old and no pads, no calling, no amplexing, and he is still tiny. If he was not a reticulated albino and so cute I would have moved him along from my collection already.
You should immediately stop feeding the bloodworms. Freeze dried food is a recipe for disaster.
You should remove your gravel as it will give you more water volume. When you can I would definately upgrade the tank. Luckily males do not get as big as females, but still produce a lot of bioload. Have you been testing your water? The "growth" you have in the tank sounds like hard water deposites. If so that is nothing to be worried about. A pic would help identify for sure.
You are in much better shape by the way then the average new misinformed person and your frogs definately could have ended up in worse homes.