Stubborn Toiletting

Well, this is a different sort of answer, but as someone who has worked in the preschool/daycare setting and helped a lot of children with their toilet learning, I would say this: let your daughter decide for herself what she is needing at this time.

Being that she is excited about school, I wouldn't make her have to "earn" it by not wearing diapers. It would be devastating and confusing for her, and children of this age do not understand how the two are connected. Plus, you have worked hard, I'm sure, to establish a routine for your day and that would fly out the window.

Consider asking the teachers what they might suggest. I have seen that children often do go back to something familiar when a big unfamiliar thing comes up, even when they like the unfamiliar thing(school!). Children who are toilet learned who ask for diapers upon starting school is extremely common. And given a chance to ask for what they are needing and have it respected, these children pretty quickly lose the need for diapers. However, make it a power struggle and it can go on and on.

And she's also told you:"it isn't fun".All-day self-regulation rarely is.

Remember, too, that while school is fun for her, there are a lot of new things to learn and plenty of teacher-initiated transitions, which means that she is doing a lot of new work within. Switching from one activity to another all day at the cue of a teacher is quite a feat for a young person, who is often very engaged and has their own interests and sense of what they want to be doing at any given time. Often, when we see children asking for diapers, we can interpret this as a message to us:"I trust you, Mom and Dad, and don't need to impress you and I need a little break from controlling myself every second of the day." This isn't about her being lazy or trying to have her way, it's about the fact that children need to have parents who are gentle with them and can understand that she's likely to be nervous about messing her underwear in front of strangers, but she does need space to have a little accident now and again and not to worry about it or feel ashamed.

Get past the power struggle, get past the diapers. It might take a month or so, but it WILL happen. Oh, and if Santa brings her a few more pairs of cute underwear in her stocking, that's fun too!

I know it seems like losing, but I'd just back off and let her relax and regress at home on her off days. Going in the potty and staying dry is hard work, and she just isn't ready to commit to that hard work all day every day even if she is capable. I am capable of never losing my temper while I am at church or school, but to ask me to never lose my temper ever is just too much to ask. At home, I try my best, but I am relaxed and comfortable, and would go crazy if I were always on my best behavior. Does that make any sense?
I suggest that you let her take the lead for a while and let her decide how often she wears panties outside of school. You can offer rewards or incentive, but for it to work, it has to be her choice. Once she has more practice, and the whole potty process is easier, it won't be so much work to remember, and she will progress to more days... or you may have to lose diapers and just randomly "find" one at bedtime.

Having been through 4 sets of kids I have learned that toilet training is one thing you CAN'T control. I would let her wear the diapers or pull-ups but since she is so capable let her do it all herself. Put them on, change them, etc. I bet she will get tired of the pull-ups eventually and switch over to panties full time. It might seem frustrating, but she will get through this phase. It might be a ploy to go to preschool every day, but she'll figure out that isn't going to work.

If you stillwant to use diapers for nap or bedtime then hide them during the day. That way your daughter has to wear panties all day even when not in school. If she makes a mess in her panties then she has to help clean up her diaper. Have her wash up in the tub with a wash cloth.
I hope this helps.

why does she need them at night and for naps? if you take away the crutch altogether she may just give up the idea that she needs them. once i started potty training my kids (and i started at 2 with my daughter and 2 1/2 with my son) i eased them out of diapers completely. of course, i'd limit liquid intake before bed and do the last trip to the potty right before bed but witin 4 days my son was accident free and my daughter never had one. (i know, i was shocked too!)

maybe you could point out to her that changing and cleaning up after diapers isn't fun for you and let her know that she can't go to school all day, every day until she's proven to you that she's completely out of diapers.