Don't listen too closely to your mother. I have always wanted a Disney wedding, so when we finally got engaged earlier this year, I went ahead and started making plans. My mom insisted that we would never get the 40 guests I was planning on in my budget. Right now we have 50 tentative "yes" out of everyone we had on the list to invite. There has only been one no... My family does not have an excessive amount of money either, they're just excited to have an excuse to go to disney and a discount!
When I spoke to my EM about dates there was no issue at all, and I'm going with the last week in April, which is right on the edge of prime wedding season. I had 3 possilbe locations in mind for my reception, and all 3 were available, so I think that as long as you're open to possibilities you can definitely get a disney wedding you'll love!