Congrats on matching!
Yes, you can always request feedback but in all likelihood, your #1 did rank you highly but the match algorithm paired individuals who were ranked anywhere from one to a couple of spots higher by the site.
Judging from my experiences on the ranking side of things, often very little seperation exists within tiers when candidates are equally strong, yet we have to create ranked lists so the difference between a site's #1 and #5 is often practically non-existent.
For a site like mine that uses the same rubric to rate people, it could something 'small' like one candidarte got 2 extra points for high quality writing style and research that puts them in a higher scoring category so that when everything is averaged out, they'll end up being ranked 1 spot higher than another equally qualified person.
And from a site's perspective, we spend more time looking for overall profiles that should fit well with sites, rather than specific candidates so we would be thrilled to match with anybody in our top tier(s) while candidates have a lot more riding on this decision. Good luck for the internship year!