Need help with interview questions, have a hard time talking about myself: who am I?

I've applied for a scholarship that will pay for my entire graduate studies. This scholarship means alot to me and it will relieve so much stress. In about 2-3 weeks I'll have to go to an interview to allow them to screen me and decide if I'll be a good candidate to receive the scholarship or not. The question that I always have a very difficult time answering is:

TELL US A LITTLE ABOUT YOURSELF

I've never been comfortable talking about myself, what I think about myself and also I don't know how to brag about myself. How do I talk about myself and not tell them my entire life story.

Some information about the school:
I've been accepted into the Rehabilitation counseling graduate studies
They focus on working with people with all sorts of disabilities to help encourage people in becoming independent and help them look pass their disabilities and life's obstacles.

Please help me focus in on what points of my life should I talk about
How do I go on this interview and not sound so generic?

I bet this may be the same for many other people but I do so much better with specific questions such as: Why did I decide to going into this field?
Oh thats a simple question to answer.

Only you can answer their statement "tell us about your self"

a tip someone told me-- when you get in the room for the interview close your eyes, take a deep breath, and be honest. if you dont know what to say tell them...

so I did.. I walked in there and that question came up. I closed by eyes. took a deep breath and said.. you know what, I was dreading this question.. I never know what to say. I dont know what you want me to say.. do you want me to say Im a good person, that I like people, that I hate spinach, my favorite color is magenta, Im kinda a control freak when it comes to neatness. I hate it when people throw their trash on the ground, I mean how much time does it take to tuck that trash in a pocket or walk a couple extra steps the throw it in a trash can... by this time the interviewer is smiling and laughing right along with me.

basically they just want to know what ever you want them to know about you.

Try to answer the question in a way that would be relevant to the person interviewing. Over the last 20 years I had an opporunity to hire a lot of individuals. I used this question as an icebreaker to get the person talking a little. Prepare maybe 3 items you want to briefly mention in the matter of 30-60 seconds. I don't believe the question is meant to be anything but a very brief greeting.

I would try to focus on aspects of yourself that are relevant to the field, or
indicate your strengths, or your achievements, or your interests, and maybe
things that you have done such as volunteer work.