Is the first day of kindergarten supposed to be this way?

Okay... I am raising my 5 year old grandson. Today was his first day of kindergarten. It was a little stressful this morning as we walked out to find a FLAT tire. I honestly hid my frustration, concern, etc... as best I could (for his sake). I called my co-worker and she picked us up and I brought him to his clroom. It took about 5-8 minutes of reurance and the teacher finally took control so I was able to leave. All appeared to have gone well-- he told me about his day and I finally stopped drilling him as he told me, "I don't want to talk anymore". He tells me that sometimes and I understand-- I know I hate it when someone goes on and on. Anyhow, he has been so grumpy and disobedient this evening. I have had to discipline him several times already. Finally, I had to give myself a "time out". I had to remind myself that he has had a big day and he is probably very tired. I tried to explain to him that I understood that this was a big day for him and I knew he was tired but that his behavior was not acceptable. Has anyone else experienced this with their kindergartner? My head is splitting from stress and already I can't wait until Friday.