It sounds like several of us are in the same situation. Dukie is 7 and chloe will be 3 months on the 24th. Same thing going on....puppy agression. I'm amazed at how tolerant Duke is of her behavior. We cheer him on..."put in her place, boy".
I really had concerns as to how this was going to work because Duke tends to be agressive. It took a month of keeping them seperate and introducing them gradually on leash. He initialy behaved agressively.lunging and making agitated noises. So to see him playing so tolerantly is really a miracle! He enjoys having her around, but she wears him out and we let him hang out in our room for quiet time without the pest.
As an added bonus he seems more receptive to people visiting, he was very friendly with my daughters friend this wevening, was even licking them and you could tell he was enjoying the attention. I think he sees the big fuss everyone is making over Chloe and wants some of that attention for himself.