Anyone feel this way about their LO?

LO is 3.5 months old but seems so much older. He has excellent head control, sits up with a little assistance, loves to "stand", reaches for things, hates being swaddled, looks around and takes everything in, and babbles like a beast. And he's coming up on 14 pounds pretty rapidly!

I guess I just thought at 3.5 months, he'd still be a sleepy little guy and not so aware of his surroundings. He even imitates us, if we stick out our tongues at him, he sticks his out at us. He's growing up so fast!