The Church considers conversion to the Faith to be a serious matter. Nothing in your thread indicates that the priest knows how much you have been studying, what you have learned, what you might have troubles with, where there may be weaknesses in your journey to the Faith, and he is responsible for determining that.
If I were he and you had just started in RCIA, I would have some hesitancy too, at least until I had some sort of conversation with you - and not a 5 minute one, either. You should be pleased that the priest cares enough both for the Fatih and for you that he is not flippantly saying “Sure, no problem; this is just a formality anyway”.
So what do you know about the Faith? History ( some comprehension of Old and New Testament, and something of the Church over the last 2000 years); sacraments, pracitices, morality, how do you answer Christ’s question (“Who do you say I am?”), eschatology ( $.50 word for where is this ultimately going) and a host of other issues.
You may be well prepared. You may have gone down a rabbit hole, or more than one. If you are already baptized, what does it mean for you to say " I accept and profess all that the Catholic Church accepts and professes"? What does the “all” mean in that sentance?
The Church does not require you to be a theologian, or to have St Thomas Aquinas memorized. But there are some issues which we consider seriously important (you can start by dissecting the Creed) and he needs to ascertain where you are in this Journey.
And the journey doesn’t end on Holy Saturday night; it just begins in earnest.
Fear not; go in and answer as best you can, and understand that if he is not comfortable, he has your best interest in mind. We have way, way too many half-baked Catholics already. We don’t need more, and he wants to be sure you understand what you are committing to, and that you are committing. Welcome to the Journey!
