That sounds like a decent rate of kicks to me, but unlike what some trainers teach, there is NO set rate for bi-fin or monofin kicks. There are too many variables....how much suit you're wearing, what the temperature is, how much weight you're wearing, where you're neutrally bouyant, how much creatine is in your muscles at the time, how long your surface interval was, and most importantly, how you feel before and after the dive.
If you're weighted heavy, say neutral at 3 metres, then it might take 5 mono kicks to get to 5 metres, then you sink to 30 metres, but it will take a lot more to get up. If you're in cold water, and are wearing a 9mm suit made of Yamamoto rubber, then you will sink even faster once you pass the neutral point, and you will kick a LOT more to get back up. If the suit is 9mm, and made of regular neoprene, you will not sink as quickly at first, and that will change the kicking rate.
If you are weighted lightly to be neutral at 25 metres, then you will kick harder and more often to get down, but will come up on 6 or 7 kicks (maybe), depending again on all the other factors.
You may hear some "expert" telling you that all freedivers should be at "X" depth within "X" amount of kicks, but I assure you that they are misinformed and probably have not dived in all the different environments out there (cold, competition, recreational, spearfishing, water salinity, etc).
The same goes for kicking styles. For a diver weighted for deep-neutral, say in competition, she will inevitably have to bend the knees more at the beginning of the descent, then evolve the kick into a somewhat straighter leg kick, then stop kicking altogether and sink. The same goes for the monofin.
Listen to your body, enjoy the feeling, and pay attention to that

Cheers,
Erik Y.