There are some things that people think when taking music lessons, or when they think about taking music lessons, and honestly it couldn't be further from the truth! Learning to play the piano or guitar would be too hard, I'm too old to start learning to play, music lessons are for children (while thinking, I wish I would have learned when I was a kid).
First things first, you're never too old to start learning an instrument. If playing the piano or learning to rock that guitar was something that you had always wanted to do, than you should do it! Yes, you won't have years of experience as you would have if you had lessons as a child, but the key to learning to play an instrument is the will to learn, a good teacher and practice. Yes, even us adults have to practice. All musicians have to practice, no matter how good you are. The nice thing about picking up an instrument as an adult is you will learn it faster than is a young child.
It's really not as hard as it looks to learn. No you won't be playing like a concert pianist after your first lesson or ready to jump on stage and shedding your solo during a rock concert. Learning an instrument starts at the beginning, and it will be easy for anyone to comprehend and work each week to gaining more knowledge and ability to play your instrument of choice.