You were legal to fly the approach. You'd have been legal under 135 or 121 to fly the approach provided the viz requirement is 1/2 mile.
The way you worded your post might lead people to believe you went below mins. Breaking out 100 ft above the TDZE would have you below mins, and therefore you should have gone missed before you got to that point.
I think you meant to say you had the red siderow or terminating bars in sight at minimums, and then picked up the rest of the runway at 100 ft above TDZE.
I've flown about a bazillion approaches down to CAT I mins, and that's the way it usually happens. You get the lead in lights, then immediately the red lights you need to keep descending. By the time you're at 100 ft above the runway, you've got enough in sight to land.