You could try sticking your leg out so she runs into your leg when she starts approaching. You could also try backing up and keeping backing up until she moves away from you.
(like if you feel her nose against your back, you could take a few steps backs and continue to back up into her nose until she moves away.)
What I do with Vega is I carry my carrot stick when I want to make her learn to walk next or behind me, not in front of me. And as i'm walking, i'll have the carrot stick waving in front of me, and if she walks too fast, she'll walk into the stick and pause, and then continue when there's some distance between herself and the stick. It also works wonders when teaching a horse to stop when you stop and not to walk in front on you.
If I go up to the horses today, i'll see if I can get a video of that and show you what I mean :)