God = Most Supreme Being
His Existence means it's not up to us to decide whether We believe or not, it's up to him,
If you don't apply this then it's not God you're asking about, you're just asking about any Stronger Being
If you wanna know or test if God exists or not, become someone worthy of being a Believer & see if it works or not,
This isn't a World to see who's Smarter or Wiser among us, it's instead about our Morals & Ethics, something We can all have regardless of Place, Gender, Age, Intellect, Wisdom, Wealth, Physique, Beauty ... etc
So instead, the more important question is, where are your Morals derived from? Where do you learn them? Why should anyone trust the person next to them? Who sets Values to anything if We are all Equals & have different Views & Preferences?
Who you believe decides what's Right & Wrong, that's who you are currently Worshipping, it could be yourself, could be other People based on different Criteria or maybe something else completely, but if you say that you believe no one & nothing should decide such matter, then you have no Values, in which case that makes you an enemy of Human Order
This isn't about God vs Science, it's not School, this is about whether you believe in Judgment or not.
Only difference is that True Believers in God believe that everything We do is recorded & we will be judged for it one day, while Non-Believers think that they are only gonna be judged for things they were caught doing by other People, that's all.