Before I turn you into a Master of Grammar, let me prepare.
Yay! I finally have a chance to correct a group of people at once!
Now, you must read the rules of this knowledge.
Rule 1: Knowledge is power.
Rule 2: With great power comes great responsibility.
Now, I will start.
"Its" is actually possessive. "It's" is the contraction for "it is" .
"Ain't" is not a word.
The words "funner" and "funnest" are NOT words.
If the next word in a sentence starts with a vowel, you would use "an" instead of "a" .
When a word has more than one vowel, it can't have "er" or "est" at the end. Correct Example: "This roller coaster is more amazing than the last one." Bad Example: "This roller coaster is amazinger than the last one."