When can I start a minor?

I asked a counselor at SPOP if I could start a minor, but she said to wait until after first quarter to see how my workload is, so now I’m wondering how late can I start a minor/possible double major

Some minors have pre reqs or an application process, some don’t. I’m thinking about a minor in business, but if I do it I have to compete to get into the classes which are like filled up on day 1. I planned out an ideal 90 units over 2 years and if everything went just right with 12 units my first term and 16 every term after that I would finish a minor with 2 elective slots to fill. I wouldn’t be starting mine till next quarter if I do it.