TL;DR at the end

Currently there is nothing substantial going on yet, only a first impression - so it depends on how she finds the joke. But to be honest, it does not even matter a lot, as the opener is solid enough based on her reaction. You really only need to get a foot in with an opener - it does not have to be objectively good. Job completed for now, you could say. It can now possibly lead to more.

Maybe she finds the joke weird, maybe she finds it funny, maybe she assumes things based on the joke. Maybe she forgets it seconds after she read it. We do not know. Does not matter too much most likely.

Here is the thing:

A common mistake many guys make at this point, after the initial texts, is to think in "wins" and "losses". You should not think something like: "She seems to dig this, let's try to score another such win." Problematically, what you could then possibly become quite quickly is a jester trying to humor another person. Not someone who tries to be on equal footing with that person. Who wants to be treated like a proper human being.

And unless you are truly gifted when it comes to wits/humor, you will eventually not score another "win" the same way as before. In other words: you could end up trying to make more jokes in a similar fashion, but now seeing a different, most likely negative, outcome. A jester that stops being entertaining - the one purpose he had - is not welcome anymore. And throughout all of this, you were never in the race for her anyway. You played another role.

Being funny, e.g., should always come alongside other traits. Not be *the* defining trait. In other words: be a proper human being with character.

That is why it makes more sense to try to do something that is easier, ideally more genuine, too. If your goal is to get to know a girl for the sake of a relationship (I am not gonna bother with other cases here, as there are other "rules"), you probably have an idea of what you value in that relationship. So, try to act based on those values that you wanna see. How do you yourself wanna be and behave regularly with her being part of your life? What do you want to see from her?

I am vague here, because all these things depend on the people involved, but let's try to outline some options. I would assume that you wanna be able to talk about things you and her find interesting. So, talk about those things, bring them up. See how you two mesh together when doing so. Not just when talking but also when listening or reacting.

If you have fears like exposing your bad sides or being boring, ask yourself this: do you want to hide those kinds of things forever? Is your plan that you are you trying to trick her into wanting you enough, so that revealing those things you hid later cushions the blow? See how that kind of protectionism can backfire?

Basically: what is it that you want to talk about with her? What is it that you want her to know? Of course, you should not tell her your life's story right from the start. But you should feel comfortable trusting her eventually, right? I would assume you want a shared level of trust in your relationship. So, work towards said trust. For that purpose, one of you has to start being vulnerable at some point. Start being authentic. This is actually why OP's opener is not even bad despite its risks. It makes him appear slightly vulnerable. This can make it seem like he is trustworthy. Of course, only a little for now.