When to apply with DIY postbacc?

Hi everyone!

I am currently pursuing a DIY post-bacc like some of our peers here, taking upper division biology courses, and continuing to take classes I am enjoying in the biology field. I have done some reading through a few of the previous posts, but have not read much in recent posts about when to consider applying to medical schools when following a DIY post-bacc structure, or whether to consider another program beforehand?

For me personally, I am taking upper div courses I did not take previously. Although I did take all pre-req classes in undergrad, I did not take too many upper division biology classes.
If anyone has previously, what would be your advice in terms of how many credits to consider taking and when to apply when you currently have a cumulative GPA that will not reach a 3.0?
I am maintaining A’s in my classes currently but have only taken 4 courses so far, which is why I figured this year would be out of the question to apply, especially without having taken the MCAT yet.

Thank you and I appreciate the feedback in advance!