Hi newbie. Welcome to shopping and to the forum, and congrats on your first few shops. Just take things slow and get a bunch more shops under your belt before you get certified, that's my advise. You may find an increase of shops by becoming certified, but since you're just starting out, you'll get more shops just by signing up with as many companies as you can, and successfully doing the shops you are finding.
In a few months, once you've hit a wall and have trouble finding more shops, then you might want to investigate certification to see if it opens more doors.
Happy shopping!