Well for starters two dates is hardly a full blown relationship. This is still very casual at this point. But I’d say context is king. If you two are texting back and forth all day a goodnight is not unwarranted. However if she’s replying slower than you like and you send goodnight passive aggressively to get a response that’s possessive and clingy. If you don’t talk a whole lot a good night may be abit over indulgent.