It's probably not kosher until you are invited; your T invited you so in the future, if you are in the mood, you can go talk to her for a bit.

I think a lot of our interactions are based on how we are raised. I still remember when my husband and stepson were going to just show up in another state at someone's house, a good/family friend but an older man, a priest, and give no warning, just show up. I was horrified and said they had to call first, make sure it was okay to come over. People have different ideas of how it should be and it can be a good idea to go with the most conservative at first, until you know it's okay to do it the way you would like.

When I was growing up, it was funny; my friends would come over and my stepmother would almost have to force them to go in our refrigerator and get themselves a drink, etc. whereas I'd go to their house, especially if I went for dinner, and there were very strict rules as to who could eat what, when, and no one was allowed in the refrigerator except the mother, etc. My stepmother would invite hordes of people over for dinner on the spur of the moment but my friends' mothers dinners always had exactly 1 serving of meat for each person, etc., "sharing" was strictly a planned affair.