“I thought I was an atheist only to realise that I had joined the religion of Science”
This can be proven not by proving the religiosity of my beliefs in science but by my rejection of god.
I believed god didn’t exist. This core idea itself is impossible to prove.
So my beliefs in scientific ideas/theories and rejection of god was no different to someone believing in god and rejecting the Big bang theory (for that – one doesn’t actually have to be religious) or evolution.