Anything is possible. However- BACKUP. BACKUP. BACKUP!!!!!
try resizing it- you never learn anything unless you step out and try it.
if everything is BACKED UP then try resizing it- if it's not full then you will basically just decrease the empty space. Linux ext3 doesn't fragment, so you don't need to defrag like you do with windows.
Again, I hope you remember that before you mess with stuff to BACK UP.