The reason for being baptised twice for me was because my old church (dispensational) believed infant baptism was wrong, as well as sprinkling. I was ignorant of the subject so I went with it and got re-baptised. I no longer hold this view. I believe my first baptism was valid, and rebaptism was not necessary.
Yep got caught in that trap myself. I was attending a dispensational church run by a former Southern Baptist pastor and he basically layed the smack down regarding my previous baptism in the Lutheran church. So with nothing to counter his arguments I ended up getting dipped.
Peter
If you believe what you like in the gospels, and reject what you don't like, it is not the gospel you believe, but yourself. Augustine of Hippo