FYI a normal reinstall will leave your home directory intact, so you won't lose anything. You'll just get fresh system files. However, if there were any files causing issues in your home directory, they will remain.
Either way, when embarking on something like this, you should ALWAYS backup your data. In fact you should always have backups anyway. I use Time Machine, and I also periodically take proper hard copies of my entire home directory and put them on a different drive even to my Time Machine disc. Mostly because my business data is literally priceless. If I lost my business data it would be a career shaking event.