Personal space

So I'm walking along and this woman is walking on the other side of the street. As we get about 1/2 way down a block she angles across the street and comes up on the sidewalk in front of me. She is walking fast, but I'm walking a little faster, so I'm gradually come up on her. We get to the corner and I'm right behind her, she angles across the street, heading left, and I'm right behind her. (This is about 3 houses from my house, so I'm cutting across to head into my yard). We walk about 15 more feet, she stops and turns:

Her: Why don't you just go past me
Me: awkwardlyExcuse me. Sorry
Her: No problem

If you don't want someone to walk behind you... don't move in front of them! I get how she feels... I'm a guy, walking about 4 feet behind her, and she is a woman alone. But I wasn't invading her space, she was invading mine. Just felt kind of awkward.