A.L.
S., please feel free to take this with a grain of salt... and it is not meant to insult you.
When you say you "recently" got back together with their dad how recently are we talking, how long where you apart and why? You need to answer none of these questions to me, but you should remind yourself of what happened in your life.
Not knowing your exact situation it sounds to me like you are moving too fast. If you are not in counseling with your partner you should be before you move your family back together. The worst thing that you could do to these girls is to make the move and change schools just to have it all fall apart again...and separate form their dad a second time. Unfortunately if you have broken up once, your relationship is more likely to end in another break up if you do not do some serious work on it.
I cannot emphasize enough that working with a professional counselor to get a more objective view of what you need to do to make this work is absolutely priceless - no matter how much you love your partner and how happy you are to be reunited. When you're in love it's easy to forget what caused you to split in the first place.
Moving to a new school/town in itself doesn't make you a bad mom, but if it doesn't last the second time around a change in schools is the least of your worries.
Good luck.