So this is a question about how I should respond to a shit test I got recently. After I ask her out to coffee, she simply responds with "lol"

Here's a screenshot of the tinder convo:

http://imgur.com/iB3ddoR

Additional info: I'm 18, she is 20, and that's not her kid. I haven't responded yet and I'm thinking just radio silence until she comes up with something better.

Any suggestions?