you have to learn to be patient. people take years if not more to master an instrument. even then, you're still learning something new every time you play or if you play in a band.
start looking at local music stores. inquire about private lessons, mention your disabilities if the teacher will think that will be a factor, and maybe they have different strategies to help you practice.
consider rending your equipment first before you buy it right away. or if you do buy, look for used equipment. you don't need to go all out right away. then if six months to a year or more, you're still playing, improving, and enjoying it, you can start to look at better equipment.
do you want to play rock, pop, jazz, blues, or other genres? you need to figure out those too, as they are completely different languages of music and reading skills.