IMHO, if you can handle Space Mountain and want to try something a little more intense (without going to the RnRC, Hulk, or Dragons level) then Mummy is a good next step. If Space Mountain is too much, then I think Mummy would be as well.
Mummy doesn't have the same vertical drops that Everest has, but there is a part where you do go backwards. In addition, some of it is dark and I thought it went pretty fast. There are no loops and/or inversions.
I was very nervous at first because my kids kept saying "Come on Mom, it's great, you'll love it!" and that's usually exactly when I should avoid whatever ride they're advertising, but it actually was fun, I really enjoyed the theming, and I went on multiple times.