How can I provide the insurance company with proof of prior insurance?

I’m getting my own auto insurance after being on my mom’s plan since I started driving. I was told that I need to go up to the insurance company with “proof of insurance for the last six months.” I’m just wondering what exactly do I bring them? I have my insurance card with my mom’s company, but the date on in for the date the card was issued was less than six months ago and I don’t have the previous card. I don’t have anything else, so will that suffice or do I need more paperwork before I can provide them with that?

I know this is probably a really stupid question, but forgive me, I’ve never had my own insurance before.