Yes, you can drop out and start over again, but why would you want to? Every school you apply to you will have to disclose that you have already taken a year of courses at another school. This may or may not affect your chances of acceptance.
I know a guy who had the extra time during the LSAT and still ended up at a T4 school, obviously extra time did not magically raise his score 20 points.
Having a learning disability may not be the reason why you did poorly. Did you talk to professors after the first semester to find out how you can write better exams? Did you contact your school's academic assistance program to see if you could get some tutoring? Did you talk with second year students to find ways to improve your study habits? Did you take an exam prep course?
Rather than waste more time repeating first year, take a summer school course and see if you get better grades when you have more time during the exam. If you do better, then you should drastically improve your grades over the next year. With your grades high enough, you should be able to transfer to another school. If you transfer, you may have to take an extra semester or year of classes, but retaking the LSAT and first year would set you back two years.