I don't see anything wrong with shooting off a friendly email to introduce yourself and to also let her know if she needs anything you are available. I think it's important for us to keep a close contact with the teachers because imo it shows you to be an involved parent who cares about her child.
In the past I have waited a few weeks first, but that was before my child got his IEP. I waited to see if he was having a difficult time which he was.
Now I plan to do it first thing since his struggles have now been identified and it's more of a "Hey, if you need my help with anything, I am here for you" plus the teacher knows that you are open for communication etc.
Theoretically the 1st grade teacher should have all of the info from kindy.
I like that you included positive points about your ds (responds well to 1,2,3 magic) as well as the cautionary points.
The first year my ds had a formal 504 in place, I didn't do an introductory note to ds teacher. I think that's part of why ds 4th grade year started off so rough. The teacher saw ds dx and 504 accommodations, assumed he'd be a difficult child, and came down on him hard. Once the teacher got to know ds, she calmed down, and ds had a better year. She ended up being ds 5th grade teacher, too, and ds was happy about it.
I think if I'd prepped the teacher (ds loves rules and routine, so follows class rules), she would not have approached him so harshly at the beginning of the year.
I've also discovered that writing a quick note to introduce your child is helpful because sometimes the teacher doesn't get all the IEP's/504's and/or hasn't had a chance to read them all. My dd went nearly an entire year once without the teacher providing any of the accommodations. I'd assumed that the teachers knew about dd 504 so couldn't understand why dd was having such a hard time.
If your school has a meet-the-teacher night before school starts, that could be another good opportunity to prep the teacher before school.
We started today! DD is in 3rd grade this year and I really wanted to make sure things started off on the right foot. The teacher is only starting her second year, and is not the one DD'd expected. So, we requested a meeting as soon as we knew the placement was finalized. The teacher was out of town until last week, but we all got together for an hour last Tuesday, during which the teacher showed DD where her cubby would be and where lunches would be stored, and explained some of the class policies (and answered a big list of questions DD had prepared ahead of time). Then DD had a reading assessment the next day and this week we met the new nurse (medical concerns as well), and attended a class get together at the park. All that really helped change a questionable attitude around, and set DD at ease. I'd really recommend you request a meeting ahead of time. First days are hard, but without some preparation they are harder than necessary.