"I can put a G sharp, let’s see, C - D - E - F - G sharp, there we go."Okay let’s compare these to the days of the week. Could you imagine if I asked you to tell me about Wednesday, and you didn’t know anything about Wednesday unless you started counting from Sunday?
[For example,] "Okay let’s see, Sunday, Monday, Tuesday, Wednesday! Wednesday is the 4th day of the week. It's right after Tuesday and right before Thursday." No, that would be silly! Without much thought about it, you know that Wednesday is the middle week day that comes right after Tuesday. And [you also know] it comes before Thursday. You don’t need to start counting at Sunday or Monday to figure out what the heck Wednesday is, or where it falls within the week.
If you’re just starting out on the piano or keyboard, you really need to think about the names of the keys the same way you think about the days of the week. If I ask you to play an F, you shouldn’t have to start at C and make your way up to an F. You just should know automatically.