You have broached this question a number of times, and everyone seems to be in agreement that starting small and working your way up to be a best plan of approach.
I have been in your shoes. I hated riding roller coasters, out of the fear of airtime and steep drops. However, I realized that starting with the smaller roller coasters helped me realize the design was not nearly as aggressive as I feared, and I worked up from there.
Here is the plan of attack I would recommend:
1. Ride Adventure Express. This is a true Arrow Mine Train - perfect for families with no steep drops or bursts of speed. Just lots of fun turns and straightaways. (And my second favorite mine train overall, a personal favorite!)
2. Ride Backlot Stunt Coaster. This is a family-oriented ride that does not feature any large drops or inversions. A great way to work up from Adventure Express, and see how you feel riding a faster-paced roller coaster.
3. Stop and reflect on the previous two roller coasters, to see how you felt. If you think they were good, then proceed!
4. Ride Surf Dog (Avatar Airbender). Wait, a flat ride? Yes - while this is technically a Disco, it will further step up the game on seeing how you can cope with spinning and decent pops of airtime.
5. Ride Racer. This is a larger roller coaster, but one that features very gradual hills and airtime hills. Nothing drastic here, just a simple out-and-back wooden coaster (and a very famous one at that).
6. Ride Bat (Top Gun). This is a slightly more intense ride than the Racer, as the suspended cars sway. But it is a very fun layout that packs in some fun g-forces and is well worth the ride!
7. If you have gotten here, you have done great! Riding all previously mentioned rides gives you a great foundation, and everything from here on out is only slightly more speed, forces, drops, etc.
8. Ride Beast. Yes you heard me. While Beast is notorious for its length, it is not notorious for its speed or drops. Seriously, the roller coaster's first drop is 140 ft., but it also has a trim brake, much like other portions of the ride. This roller coaster is about ride duration, and honestly does not pack any major airtime or steep drops. If you can ride the previous rides, Beast is an easy step.
9. Just keep going. I would probably ride Vortex next to introduce inversions, and then move on to Flight of Fear, Firehawk, Delirium (Giant Swing), Invertigo, Diamondback, and Banshee. I do honestly skip Drop Tower as I am not a fan of drop towers. Once you get the momentum going, you realize the biggest barrier is all in your mind for riding roller coasters - the actual riding is not nearly as bad as you fear!
