How hard is it to learn to play an instrument at the age of 25?

I’ve always wanted to learn to play piano, and found some ads on craigslist for lessons, four 30 minute sessions for 60 dollars.

How difficult will it be to learn? I can’t read music, and have never really played an instrument before. I wish my parents made me learn when I was younger.

Any tips, thoughts or suggestions are appreciated, thanks =)