Two points.
The first is that matter, form, and intent, if not wholly compatible with the Church’s understanding of God, has been a great impediment for Mormon converts at one time.
catholic.com/quickquestions/why-doesnt-the-catholic-church-accept-mormon-baptism
Early on, the Church considered Mormon baptisms valid but reversed this decision when the Church came to understand more fully that the Mormon notion of the Godhead was wholly incompatible with its own (although correct form, matter, and supposedly intent were present at the initial Mormon baptism).
Now, I’m not saying that your Baptism actually was lacking, but the theology behind it is unclear to the hierarchy in light of the precedent I just gave.
Second, the One who didn’t need to be baptized
submitted. He was wholly pure and sinless, and would later send the Paraclete to Baptize with Fire as John predicted. Initially, John even refused to baptize Jesus. The Christ himself didn’t “need” to do it (there are many layers of understanding why He did, not all of which apply to us humans), but He did it.
Instead of implying the Church is legalistic in caring deeply for your immortal soul to “make sure,” I’d thank it. Rather than going on to receive the Eucharist unworthily, I’d be very, very grateful.
Who are we as individuals to stand on legalistic principle to say “no” to anything conditional which offers us Sacramental Grace through His Church, knowing the lengths that Jesus submitted to for us, especially in the case of His unnecessary Baptism?
Perhaps you posted it and I missed it, but suppose the Congregation comes back (after months) to say that your initial baptism was theologically unsound, although the proprieties were observed? Would you then do the twelve minute ceremony or just walk away?