Graphic Design Portfolio For Uni

I'm really worried about having to bring a portfolio to my interviews for uni next year demonstrating my passion for graphic design. What do I put in it?

For a start I am taking a level product design, so the only material I have are designs for products I made last year.

I have a portfolio from when I did GD at GCSE, but is that too old?

I haven't quite got the hang of Adobe yet so wouldn't be able to produce polished designs. Could I put in some drawings instead?

And am I meant to write about what I have produced or could I tell them on the day?

I'm hoping to go to Lincoln or Coventry

Thankyou!