I don't see any problem with looking around while you're waiting; then you might have more irons in the fire if you get denied. They aren't interested in what you are doing right now, they're reviewing the paperwork, etc. and if you got something you enjoyed going now, you could ditch the SSI or not, whatever, I don't see you ditching the process now, looking around. Just don't overdo it. Look for volunteer jobs that might be interesting or let you learn new skill/keep practicing skills you have or little sorts of jobs/ideas for jobs for after you do/do not get SSI, etc. It won't be enough to really live on, SSI, will just "help" and will be reviewed periodically, etc. anyway, so at 23, nothing lost by seeing if you can't cobble something better together.