Its pretty impossible to do with dive number alone.
For example someone with 200 dives, 50% in quarries and 50% on 15m tropical reef in warm water and no current is probably less experienced with varying conditions and scenarios than someone with 100 dives all in the sea and has experienced currents, cold water, rough seas, low vis AND been abroad to do the warm water thing.
Width of experience counts for more than numbers.
You could in theory have a padi OW "beginnger" with 200 dives and a padi AOW/Rescue with 20 dives. From that scenario, certification level isnt a good guide either.
I do tend to agree though that ALL divers should receive rescue training as soon as practical. Without that its a little unsettling for the buddy.
You'll probalby find yourself when you no longer class yourself as a "newbie". You'll get to a site, make your own personal judgment about conditions without even thinking about doing it and on dives you'll be very relaxed and know exactly what you're doing throughout. When those things start to happen, for those conditions at least you wont be thinking "im new at this".
In short where your knowledge of a site or dive would allow you to tell others (if asked) what to do and what is happening as opposed to following the leader or waiting to be told what to do.