Subscription not using gateway

Hi, I'm hoping someone can help.

I have membership plugin installed. I am using an initial 30 day free (which I set to 1 day for testing). After the free period then a recurring monthly billing happens using Authorize.net.
So I had all my test users set for the trial and the next day I login (after 1 day) and expect to be presented with a message about needing to enter credit card info before the recurring membership goes into effect. Instead I find all my test users have automatically been switched from free to paid recurring period. At no point in time is a user requested to enter Credit card information. I do have the gateway active.

The plan here is to have users register on the site, they will not be asked for credit card info until after the free trial of 30 days. So they have free access and then after the 30 days the should get a message about needing to enter credit card information to continue with their membership.

Any ideas or suggestions for which direction to go with this?

Thank you in advance.