Was this appropriate behavior or did it cross the line slightly? (Details inside.)

My family attended a gathering Friday evening where there was a small buffet. It was a group event and pot luck so there was no specific hostess. When it came time to go through the buffet line I quietly grabbed a plate and started getting food for my husband. As I was going through the line another woman got a plate and asked aloud what she could get my husband to eat. I responded by saying “I have it.” So my question is this, is it appropriate for someone else to want to make a plate for my husband or should it be automatically left to me? I admit it, I was a bit put off by her offer. It didn’t make me angry, but just didn’t sit well with me and for the record, I didn’t make any kind of a deal about it. Am I being hypersensitive here?

P.S. There is a very good reason for my husband needing someone to get a plate for him, so the issue isn’t whether or not he should be waited on.