[She spots him immediately, it's hard not to with that miserable body language, but it looks like he didn't see her. No problem! She has a bike and a sense of purpose. If anyone asked her about her choice of actions after the fact Aerith would explain that she didn't want to make Shinji uncomfortable by making any physical contact with him but the truth is that her first thought was preventing him from getting away without talking to her. He could always walk around her and keep ignoring her so it's not like she's trapping him here. Plus, Haruhi said he would answer their questions! With that self assurance in mind, Aerith speed walks her bike over to Shinji and stops it right in his path.]
don't mind Aerith, she's rude and overly familiar
Hi, Shinji-senpai! Can I walk home with you?