Why didn’t you just say you don’t have an Insta account, and just mention that you’re just quite a private person (don’t need to go too heavy into that on a first date)?
There are some people who care way too much about it, but I feel like most people would be more on guard because of the weird explanation for having one that barely exists than the lack of one at all.
In terms of online presence I think one has to be careful about becoming too private - at what point do you become so untrackable that even people you would like to find you (I.e. old friends) can’t anymore.