What I do or are doing is have my piercer do my gauging up for me, he uses tapers and I supply the tunnel/plug.
Doing it this way when you are starting out makes sense to me as if you are doing it yourself and you feel pain you will stop.
I also started with an initial 4mm / 6 Gauge Cannula Needle piercing as I had not had been pierced before.
The above is all dependent if you have a local piercer who can do stretching and that you trust him to do it correctly and safely.
These are really important as some think they can but maybe give bad advice and stretch you quicker without allowing the tissue to heal inside the hole.
In the end the decision is yours and yours alone.
I hope this is of interest.
Regards
Dr Rob.