Meditating is not necessarily about the quality but more about the intention and action. Your mind is going to drift ALOT, the key is going back too the mediation. If you are doing a breath mediation when you think of something go back to counting your breaths and focusing on that. Most people can't meditate more than 5 minutes but the more you  do it the longer you will be able to mediate. 
The benefits of mediation include being able to focus on things better, being less neurotic, and being able to have a greater sense a of self. 
To learn how to meditate click here