I was brought up Catholic and went to Catholic schools till age 16. I never felt brainwashed and met some lovely priests, nuns and teachers (and the odd not-so-nice one). My mother was from a staunch Catholic family of several generations, my dad wasn't sure about it all. My children were baptised Catholic but neither they nor I go to church nowadays. Even so, I can say I am simply not sure about the afterlife and I don't think anyone can be - religious or not. There is lots of scientific evidence to the contrary and yet there are unexplained gaps. The bible could be a simply work of fiction, full of lovely (and not so lovely) stories, anecdotes, parables and so on.
If there is a God, and an afterlife, I believe it will encompass all religions as well as the non-religious, so long as they have lived decent lives. My mother declared she would not meet my dad in heaven cos he wasn't a Catholic!!!
In my teens a bunch of us used to have seances and believe me they were quite an eye-opener for me as whatever "spirit" we called up seemed to know things about each of us that none of the rest of us knew. In my case it was the name of my first dog, and I am 100% positive I had never mentioned it to anyone in the group. It was an unusual name and she had died when I was 4 years old, before I had moved to the town I lived in at the time of the seances.
So I have an open mind on it all. I can't see any other option.