Opening the conversation after offending her

We're both 20, for the sake of it.

This girl and I got talking on Tinder a few months back, and although we couldn't meet up for a couple of months, we kept talking. When we did see each other it went really, really well, and she said that she really liked me after we kissed.

We were then going about our second date, and set it up. However, a couple of days beforehand, I was joking around without realising she was in a bit of a bad mood, and I ended up annoying her with one of my jokey responses. Also, I'm rather inexperienced, and I didn't want to come on too strongly to her in the early stages, so I left most of the initiating to her - she clearly wants me to show the same effort now because the last message she sent was "I always have to say something first".

I sent a quite casual apology to her the next day to try to gauge how annoyed she was, but received no reply. Normally, I'd write this off and move on, but even after four days of nothing from either of us she's yet to block me on social media, so I'd like to make it up to her.

Now, I don't know what's the best method to go about this. Do I open with a more in-depth apology to show her that I know I screwed up, or do I just open with a casual conversation starter, like "hey, hope you've been keeping well the last few days" just to show her I am willing to initiate the conversation? I really enjoyed my time with her on our first date, and I'd hate to mess it up.

Just ask her out, pretend nothing happened.
If she ignores it move on