Mine was when I was 11 (or 12), in the PCA. I was born into a church that believed in baptismal regeneration (Disciples of Christ I believe, but I was so young when we left, so I really don't remember) prior to joining the PCA, and both older sisters were baptized as believers. I hadn't reached age at which I could be baptized into that church yet when we moved, so I was never baptized into that church. My baptism was at some point after starting the Communicant's Class at the church I ended up growing up in. So I have a distinct memory of it. It was nothing particularly special in terms of ceremony, but certainly was a significant moment for me in my life, and walk with Christ.
Side note...my three month old son was baptized yesterday. His grandfather (a TE in the PCA) performed the actual baptism. It was a really sweet full circle moment between him and my wife. They have a very rocky history which has been being reconciled for seven or so years now--since before I came into the picture. Yesterday was, especially those who know the history between my wife and her father, a wonderful picture of how God can restore the most broken relationships.