The ticket is confirmed with the birth, you will be given a coach number and a bunk number. IRCTC Indian Railways allows the reservation for 90 days from the trip, so it is very likely that you have a confirmed seat if you have registered before.
RAC (Reservation against cancellation):
If your PNR status is RAC, it means that you have a confirmed reservation but only with a sitting accommodation. The berth is not confirmed, but it can be if someone cancels before you on the list. You can get on the train and sit on two side chairs.
WL (Waiting List):
The status of WL pnr means that it does not guarantee any type of accommodation in bunk beds or seats. They will be accommodated only if enough is confirmed or RAC ticket holders cancel their reservation.
RAC / WL [num]:
If you obtained an IRNPc status similar to this WL21 or WL12 or WL [any number], then the number indicates your position in the queue of
when the IRCTC reached a maximum number of reservations on the waiting list too, it closes the reservation system and regrets that the reservation cannot be made at this time.