During elementary school one of my close friend groups was composed of three persons all living next to each other. Myself (m/22), another guy (m/22) with whom we are still best friends and hang out everyday and this girl (f/22) who moved away after elementary and we both soon lost touch with her afterwards.
Last week by chance we met up but we were both with our families and we merely said hi, and asked a question or two and then we parted ways. To be noted I was a bit taken aback and was a bit awkward, since I was already lost in thought and didn't really expect meeting her. My sister also noticed she also seemed taken aback. Afterwards I waved at her in Facebook Messenger and she waved back. Then I sent her a message (about 30 minutes after seeing her) asking if she wanted to grab coffee with us sometime but she never answered.
Around here it is extremely common to propose to have a coffee for any kind of meetup and since I mentioned both my friend and I, I find it hard to believe she mistook my invitation as anything weird. I haven't contacted her at all since then but I would still like to catch up with her.
How should I proceed?