should I have thrown a flag??

[Bubba10Dara]

I was working a varsity game Friday night. This happened on a kickoff. The ball was kicked down the middle of the field and was caught on about the 10 yard line. I was working head linesman and called a holding on R on about the 40 yard line, so I dropped my flag. I would say the holding happened about 7 yards off the visitor sideline. The run ran up the home sideline and ended on about the 25, total return of about 15 yards. So in short I called a hold about 40 yards away from the ball.

Should I have thrown the flag or waived it off, going to The guys in my crew said I should have thrown it, what do you think.

Thanks