My little boy 3 at the time, (this summer) LOVED Jimmy, although, after the first time, he REFUSED to ride in the moving seats...... so the next 900 times we rode it, we did the stationary seats. It is GREAT, I really liked it. IMO, it is MUCH better than the HB ride that was there........... guess I'm into the nick characters since I have a little one......... anyway, he liked shrek, but it did scare him a little bit........ not bad, just a little, when it was over he said he liked it, but he wouldn't go on it again.......... I think he just preferred Jimmy, since he LOVES jimmy and spongebob. I think your little one will like them both, and can certainly go on both..... I'd say try it, and see......... shrek was not scary mind you, just a lot going on, and the seats move, and stuff........ don't wanna give too much away....... it is one of my fav. things at Univ. you'll love it. As some have stated though, especially if you are not staying onsite, get to these EARLY........... they get LONG lines.
Have fun................ can't wait till Nov........ when we go back!!!!