Our 30 year old daughter who just had her second marriage will move to a small condo with her new husband and son from her previous marriage. I asked if she could take a lot of her boxes that I took out of attic and still left many boxes of baby clothes, etc, up in attic. She needs to go through all the boxes as they are apartment things she could use as well as items for her son. A lot of boxes are college books and tons of boxes of memory items as well as books and notebooks from school that need going through. She has needed a lot of help over the years and we have always been there to help as she is somewhat weak from immune diseases. My husband and I want to move in a couple years and I want to start cleaning out attic now. My daughter always seems mad at me if I ask for things that I would like such as this. I watch my grandson weekly sometimes twice a week. I'm older and tired. Am I being selfish? Our daughter talks a lot about setting boundries, except when I try to say what I'm bothered by I feel she gets angry.

Tell your daughter to take them or you will donate them to a charity or discard them. Don't let her take advantage of you.

This cannot just be about boxes in the attic since she hasn't even moved yet, so what's the hurry and why do I think there is more to this than just about boxes in the attic? What else is going on here mom?

It does sound like you are asking about this at a tough time for her - just remarried, still has small child, moving to a smaller place. This does sound like it's about more, and I'm wondering if the boundaries she sets, all while asking you to babysit, seem like an unfair trade, and this is the result.
Can you talk with her about a bit more 'fairness' to you as something of a reward for what you do? Try to do it at a quiet time so that it isn't full of emotion. Maybe even write it as a letter, over and over until it's right. When you can sit down to talk, you could possibly make a list of concrete things and times that would make you feel that you are part of their lives, and make her feel that she still gets her boundaries.
This is an age old problem of parents!

If all this fails (and you may have better ways of doing it), then wait until 6 months before you start talking to real estate brokers. Tell her in writing that she has 60 days to get every box out (her husband can carry them) or you will pay to put them in storage and pay one month's rent. That is actually a common solution used by many parents, and also by couples breaking up.