My baby is 18 months!

Liam won't be the baby for much longer and he's not really a baby anymore.  How is he 18 months already.  Time is flying by and he is definitely growing up. He thinks he can do everything the big kids do.  He prefers a regular cup to a sippy cup.  He tries to hold onto the rail and go down the stairs forward facing.  He wants to sit in the big kid stools to eat.  He brushes his hair.  He wants to hold his own toothbrush.  He even tries to change his diaper.  He is so observant and aware of everything.  If anyone has a treat, he needs one too.  He doesn't like to share his food at all.  He can use a fork and spoon really well.  He feeds himself everything using a utensil except I won't let him feed himself yogurt because it's too messy.  He has been taking one good nap a day just after lunch.  He can run pretty fast.  He is learning how to jump on the trampoline.  He loves the swing.  His favorite toy and activity by far is anything with a ball.  He can be  found holding a ball at almost all times.  He wakes up in the morning and will go down two flights of stairs just to get a ball.  Sometimes he will disappear and then reappear a little later with a ball from the basement.  I finally got a basket for upstairs with balls in it.  He likes to play catch and has started kicking the ball too.  He likes shooting the ball in the outside basketball hoop which makes for tired arms for me.  He loves music.  When we are in the car and he hears music, he starts dancing or singing if it is a kid song.  He can do the hand motions for Wheels on the Bus, Once There was a Snowman, and Popcorn Popping.  He loves little girls and giggles and tries to say hi whenever he sees one.  I think he's going to love this little baby girl.
Since he is 18 months old he can start nursery.  I dropped him off and he seemed okay so I left.  A few minutes later we got a picture text from the nursery leader with Liam crying.  I went in and stayed with him the rest of the time. He was clingy for a little, but then he warmed up and had a great time.  I think if I stay with him for a few more weeks he will be okay.