To further clarify........Catholics believe Jesus ascended into Heaven, it is NOT required to believe Mary was....though I do realize some do. I am speaking of what the Catholic church teaches as required beliefs....you are mistaken if you think that.
Mary was assumed into heaven. That is not the same as ascending. She was assumed into heaven by the power of Christ.
Catholics are to believe Mary was immaculately conceived and that she was bodily assumed into heaven.
There are other universal teachings of the faith that did not have to be defined ex cathedera to be regarded as binding on the faithful. Such as Mary being a ever Virgin. This means not only was she a virgin when Jesus was conceived and born but she remained a virgin for the rest of her natural life.
Apparitions are a matter of private devotion not public revelation so we do not have to believe in them.