I'm 30 and my mom is 61 (don't tell her I told you...) and I've been a Commando since the very beginning of my WDW obsession. Mom and I have been to the parks together 3 seperate times, just the 2 of us. It's a great time to get away from the stuff at home and just be together as a family. I found that my mom LOVED the live shows-- especially Festival of The Lion King at Animal Kingdom. In fact, we saw it 3 times while we were there, and she said she thought it was better than the Broadway production!
Also, me and mom love to shop, so we made plenty of time for that, at Epcot and DTD. (We also enjoy a good glass of wine, so we sampled wine in different countries, but I think you may be too young for that!) Other than that, she would wait in line with me on the 'big' rides and then take the chicken exit and meet me out front, so I wouldn't have to wait alone, and she wouldn't have to wait in the hot sun.
Just have fun and remember to really cherish the Disney time with your mom, because long after she's gone, Disney will be there, and you can go back and say, I remember when Mom and I got soaked on kali River Rapids... (that happened to me!) Have a great time!
