I agree with Tegan!
Just play it cool and laugh it off!
And stop thinking you did something wrong! From what you have said, you really havent! You both agreed that it was best not to make anything of it and until she tells you otherwise, I think you should jsut leave it at that.
I think that your cousin Tara is maybe a bit of a hopeless romantic, you could possibly have a word with her about it, but i doubt that will change anything
Some people jsut cant help but try and match-make lol!
Anyway, I hope you have a good weekend!