I know how you feel.
I love both
Tess and
Tessa , but I don't think it can stand on its own. I have put
Teresa and
Teresia on my list just because I want to use
Tessa, which is stupid. I should just go ahead and use
Tessa then, so I'll encourage you to do that.
I'm rather strict about full name vs. NN , but there is nothing wrong with
Tessa as a full name. It isn't childish or flimsy or overly cute. It's not something that will make people go "What?! That's your NAME?" (Like Pooh or BooBoo or Peep or whatever.)
Tessa is stylish and feminine, to me it feels both classic and modern. It is spunky without being boyish, it is feminine in the right way - delicate without being fragile and frilly, just sweet and sensuous.
Maybe my main issue is that
Therese (+ thousands of spelling variations) was very common when I grew up and
Tessan was the standard NN for it. When I got older I met a
Teresia who was called
Tessie, and I found it so much more appealing. If I (in Sweden) ever met a woman who had been named
Tessan I would find it ridiculous. So perhaps that's why I think
Tessa can't stand on its own.
I hope I can change my mind though since, like you, I'm not over the moon about
Teresa, I just love
Tessa.
Possible other full names - Thalassa ,
Theodosia ,
Tanesha ... nah, I guess not.