I think just encouragement and her feeling safe is a big part of it. My second daughter didn't walk until she was almost two and even when she started, she was real cautious and

-- insecure looking when she was walking -- especially outside. She was

when she was younger though -- RSV and was held a lot consequently.
My first daughter walked when she 9 months old and my son walked when he was about 14 months old -- every child is different!
I was only 23 when I had Olivia and I don't think that that has anything to do with how our children grow develpmentally -- I could be wrong, but I feel that as long as you are attentive and encouraging, that that is what they need to blossom.
I would say just keep up with what you are doing. Do you have any pets? My oldest daughter was really interested in our cat and was eager to get a hold of him -- I think that was an encourager for her. Sometimes also when they are around other young kids and see them interacting and moving around, it encourages them to do the same. Since it is warming up, going to the park and watching other kids and just encouraging playing -- walking, etc, might be good as well.
Good Luck!