I think deliciousdish and digdug have said it all. You're a great mum and it's clearly obvious through your posts about them that you love them very much and are proud of them. She may feel upset that you can't be there for her, but this is a great oppurtunity for her and afterall, she wouldn't be able to do this without you. She'll be glad of this in time (in fact she's probably greatful for all you've done now, if she's showing it or not). Don't feel guilty, your kids love you..... and I thought you had a certain fairy that's helping you banish these kind of thoughts
Have a safe trip home.
Molly