Your height wouldn't qualify you for Social Security disability benefits all by itself, especially since you have demonstrated that you are able to work despite being short, but it could be a factor considered by the agency if you had some other medical problems. In Social Security, the name of the game is precluding jobs. It's common sense that there are some jobs you can do at your height, and some jobs you just can't do at your height. If you had some other medical problem which prevented you from doing any of the jobs you can currently do, and your height prevented everything else, you could then make a claim for Social Security disability.
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My colleague Mr. Bordelon is correct. By itself, being short is not enough to be eligible for Disability or SSI benefits. However, if you suffer some other qualifying impairment (whether attributable to your height or not), you may be eligible.