Many people, priests included, are unaware of how the “Big Five” groups of the consecrated religious operate - especially secular orders.
You may already know this; the Secular Franciscans are Franciscans. They are just as Franciscan as the Friars and Poor Clares. When you join the SFO, you become a full-fledged member, which includes following a Rule of Life.
What’s important about this is your canonical place within the Church also changes. This is not the same as joining the Knights of Columbus or the Catholic Woman’s League. The SFO is not a lay association, and certainly isn’t like being installed as a Extraordinary Minister of Holy Communion or being installed as a reader and/or lector. You become a member of the Order, and with that your state within the Church also changes. Your priest no longer has the same canonical authority over you as he once did, you now have a Superior. Your Superior is whom you will go to for direction, guidance, and at times ask for permission.
Example; say you are a man, and you feel called to be a Permanent Deacon. Ordinarily you’d talk to you parish priest, right? As a Secular Franciscan, you’d talk to your Superior, and if they say “I don’t think you are called to this, I’m going to say 'no” for now". That will shut the door to being a Deacon, until (or if) the Superior changes their minds.
Essentially, it works as follows:
It used to be; You —> Priest —> Bishop —> Cardinals —> Pope.
It will soon become; You —> Third Order Superior —> Congregation for Institutes of Consecrated Life and Societies of Apostolic Life --> Pope.
This is a huge deal, and the priest (especially your parish priest) needs to be aware of the ramifications. I would definitely bring someone to help explain things.