What does it mean when he doesn't follow me back but he likes an old post?

So I went to a house party last week and met his guy who was really nice and attractive. He asked me to sit with him and we got to know each other a bit but it got cut short when my friend had too much to drink and i had to take her home. Before I go into the uber I ran back into the house to grab her coat and when he saw me he got up and came up to me, he asked if I was okay and I told him i had to go so he helped me find her coat and before I left I found the courage to ask for his snapchat.

Something about me is I'm an extremely shy person and am very scared of rejection so I'd never message first. But I am really attracted to this guy and can't stop thinking about him. To give him a hint I liked him I found him on instagram and followed him so he can see that I haven't forgotten about him. He didn't follow me back but he liked an old picture of me that you need to scroll down to see as it's not a recent. What could this mean? Interested or not?

I know I sound crazy but I'm never like this I'm just really attracted to this guy and want to know if it's worth trying. Also I have to mention that he hasn't messaged me yet either