I agree with Susan Sisson’s answer, and refer you to Nick Nicholas’ answer to Why do we need to capitalize “I” and the days of the weeks in English?
With reference to OP’s rather defensive comment:
You can do as you please. And in turn, we get to react as we please. It doesn’t hurt our brain when you deviate from the community norm. We just get to think you’re an oddball. Which, despite the UK’s celebration of eccentrics, does mean your message ends up less, not more effective. And again: there are areas of life where innovation and rule-breaking advance humanity. Punctuation is not one of them.