Firstly, Mazal Tov! May your daughter and her fiance merit to build a Bayit Ne'eman b'Yisrael – a beautiful Jewish home – and may God bless them with many, many years of health, contentment and continued growth together.
Normally two people escort the bride down to the Chuppah but there are many different customs and I have been at a wedding where the father took his daughter down to the Chuppah alone. I would recommend that either you or your daughter speak with the Rabbi who is going to be officiating at the ceremony and ask him what you should do. As he is the Rabbi the decision is really his and whatever he decides that is what you should do.