Does your mind ever wander? Great, you are alive and human!
The fact that the mind wanders is as common as the desire for food or sleep. The human mind just does. The mind will produce thoughts on its own. But that does not mean you won't be able to meditate.
Why meditate? It’s a good idea to have motivation in regards to anything that we do. For meditation, we may all have slightly different reasons, but in the end, they most likely boil down to happiness in one way or another.