Where did this go wrong?

I have 5 sleeping kids. One of them has school, the rest are off school. My husband has left for the day already. The 12 yr old who has school rides his bike to school every day. The weather is beautiful. This morning he has to be at school a half hour earlier than usual. I wake him a little earlier than usual. I expect the morning to go smoothly, as he will ride his bike and the other kids can just sleep in. He wakes up seriously crabby,
"I can't ride my bike to school, it's so early!" (it is no longer dark outside, I wouldn't have him ride in the dark)
"No, dear, it is fine, you can ride. Everyone else is still asleep."
After sulking in his bed for 10 minutes he says,
"Well I need to shower and then I will be late!"
"If you had gotten up 10 minutes ago, you would be finished showering by now. Not my problem."
And he leaves the house texting me on the way that he is stopping at Einsteins for breakfast and that he will NOT be calling me when he gets to school. (something I insist he does every day when he rides his bike)
I text back that is fine but he will lose his phone and all independent privileges.
Oh, the teenage years have begun. Trying to figure out where I went so wrong this morning. My sweet boy is getting an attitude and I really do not like it :(