Well, age is something that has few indicators. With very young Parrots, we at least have stages that provide some idea of general age. Your first photo is of a young baby, and appears to have its first set of feathers coming in. The second is of a older baby approaching 9 to 12 months.
I do not consider myself an expert on Alex babies, so if a Alex expert jumps in here, their classification of your Alex's age will be better.