You are definitely not alone!
Thank goodness that almost all of our family and friends know the proper "terms" when it comes to adoption language. I also don't have a problem educating people when they ask.
But the one time (I will never, ever forget) that something like that happened, was when we were finalizing DD's adoption and we were leaving the courthouse, and we were all feeling so good, and my MIL asked me "Are you going to call DD's real mom and tell her" OMG, I was so upset. The sad thing is, is that she felt HORRIBLE for saying it. She is from another country and sometimes gets her wording mixed up, and she did apologize, but nevertheless, I had hurt feelings over it. DH was upset as well. After that day, and that was almost exactly a year ago, we haven't had any other issues. At least any that I know about!
Same thing; don't want to take anything away from DD's birthparents, but DH and I are her parents. We are Mom and Dad....period!

__________________
April '07 Signed with Facilitator
August '07 Matched with emom
October '07 Babygirl M Born

December '07 Adoption is finalized
Blessed with the most wonderful baby girl in the whole wide world!
Starting the process again for #2, June 2009