OOPS! It may be you were not quite tactful with your response! But at least you got the point across that you want to keep your beard and that her comments will not deter your efforts. It is just that you could have done it in a better way.

Your wife will get on board, but with more time. This is a new appearance and she needs to get used to it. It could be that her friends are poking fun at you and your beard and both she and you need to ignore them. I found that to be the case big time. It was my wife's friends stating things about my beard. We both ignore them now and the comments are much less.

Now you might have stated to your wife: I know that you may not like my beard, but I really do like it and it is something I want to do and it is right for me. I do not tell you how to wear your hair or even what style of clothes that you wear. For me I am wearing my facial hair the way that I see fit and that is with a beard that is growing bigger." Or something like that. That may have scored just a few more points.

Well keep on growing and enjoying your beard and do not worry about what others think.
Patrick