The Text of the Betrothal Blessing
Question
Answer
Hello,
There are several explanations:
The Rosh writes that it is to emphasize that only a chuppah following kiddushin permits.
The Mordechai (brought in the Hagahot Asheri) explains that according to the custom of performing kiddushin under the chuppah, the chuppah precedes the kiddushin.
There are other explanations as well.
Source
Rosh, Tractate Ketubot, Chapter 1, Sign 12
And therefore also the chuppah precedes the kiddushin to say that it permits us the married through the chuppah that follows the blessing of kiddushin:
Hagahot Asheri, Tractate Ketubot, Chapter 1, Sign 12
Because sometimes they perform kiddushin at the time of the marriage blessing, and then the introduction to the chuppah precedes the kiddushin, as the introduction to the chuppah, when the bride is given to the groom in the morning, precedes the blessing. Mordechai: