Alot of people discover their talents when they have a stressor in their lives. I learned my artistic stuff mostly as a child, starting at age 5 or so, (I don't remember earlier), because of my turbulent parents and being alone alot.

I went to art school after I received my professional training and license when my husband was drafted and went to Vietnam.

I did some college level post degree training in my 20's and early 30's. It has been a great outlet for me and mentally liberating. All my training is in fine art and design. (no real commercial layout training at all).
So I always encourage people to let their children bloom if they have a talent (mine discouraged it), and to try their hands at something in adulthood as well. Art work and personal expression I think are valuable and help with illness and stress, besides being valid on their own.

The use of the mouse on any graphics program can be frustrating. You can crop and do some pixel photo retouch with a mouse, but mostly with everything else the pen/tablet are better. The newer tablets allow erasure with the pen, even, making it easier yet to delete or change.

I'd get the tablet and the new Paint free program, and that way you can use it right away. You might find the pen easier on your hands than a mouse for everyday work as well!

I am always here, and you can PM me anytime too.