There are no limits in SFI.
Everyone has the same opportunity, it's up to you, and only you, what you will be on the end of the month, and also every month.
The best thing is that even in the first month you can be BTL, STL, GTL or PTL.
We have our team liders to help us when we need the help, all you need is to asc.
Hope that i help with my answer.
Good luck in your work.