Question on when a catch is completed.

[TCGRACA]

I'm not sure if this applies or if I should start a new post, but in a youth game (little guys) on May 1, (in which fumbles are dead as soon as they hit the ground)the quarterback bobbled the snap and caught the ball on its way down. As he caught the ball and was continuing to pull back from the center, the tip of the ball touched the ground (I still can't say whether the ground provided that little extra help in maintaining control, though). Neither the Ref or I (as linesman) blew it dead but let play continue. Both of us thought that since he controlled the ball it was not a fumble (even though the tip of the ball did hit the turf). The opposing coach went ballistic, of course, and he kept yelling at me that it hit the ground. I just calmly replied that I did not see a fumble. Since this was fourth down and the team ended up making the first from this play, it became rather pivotal in the scheme of things. I'll take any and all lumps coming to me if it seems like we blew the call. Any thoughts?