Three years ago as I prepared to send my first off to school it did feel like I was going to be losing a large part of her life, she went to pre-school but I could drop into pre-school any time I liked and they had a daily diary so I knew all she was getting up to where as with school I felt like there would be this huge part of her life that I would know very little about. She is a late May birthday and the youngest girl in her very top heavy year group and even though she has speech issues I didn't have any worries about how ready she was for school, she had been very ready for some time, an independent spirit from birth she couldn't wait to be at 'big' school and to be honest I was looking forward to being able to spend more time with ds who was 18 months at the time as he had always had to fit in with dd's weekday routine.
Everything went very well with dd starting school, she loves it and is very happy with lots of friends, interestingly for those with children starting school either knowing only one or two or non at all, in dd's year 21 out of the 25 had gone through the village pre-school (including dd), on her first day dd came out best friends with the 2 'new' girls and still is to this day, even though one of those girls now lives thousands of miles away after moving back to her home country last year. Over the last 3 years we have had a few children leave and a few new ones come and if you were to look at the class now you would never ever know who knew each other from pre-school, it was like that after the first few weeks so really, don't worry about that aspect!
As a parent your involvement and knowledge of what is happening at school does depend on the school and how good the communicating is. My fears about being excluded from a huge part of her life were completely unfounded but if you are unhappy about things once they start just go and talk to the teacher, they can't know something isn't going well unless they are told, it is all about working together and it can be important to remember that.
Now I am at the stage of ds starting in September and although I am reflective when it comes to thinking about him starting his school journey, sad isn't the right word, he is my last baby and even though as an easly March birthday he is older then dd was starting is is far less mature, he has much worse speech problems and I do have some concerns although I have the benefit of having had dd go before him so I know that school will work with me to ensure that ds has a good school experiences and any problems are overcome together. I can't stress enough how important it is to work with the school and teachers, they are not some force trying to take our babies away from us and take over their upbringing. Most schools will work with parents to build this partnership that will give your children the best start possible but unfortunately, just like us as parents there will at times be problems and things may not go to plan, teachers are just people and are fallible, most important thing is to keep open lines of communication.
One last thing is that I see a fair few of you are worried because your school experience wasn't very good and your child is very like you in personality but please remember they are not you, they are not going to the same school with the same teachers (in most cases!) as you did and most importantly they have parents who understand school can be hard. Talk to their teacher about your concerns right from the start, don't wait for a problem, some schools give you the chance to meet with the teacher before the children start and you can bring it up then, if not just ask the teacher for an appointment to chat when school starts, the more the teacher understands about your childs personality the best start they can be given.
Sorry for the supper long post!