No, it is not good to go from no ear piercing to a 6 gauge. you can tear your ears. there is a reason for the smaller sized gauges, it stretches your ears slowly and prevents your ears from tearing. the only way you can go from none to a 6 is if they "punch out" your gauge, meaning they would punch that sized gauge through your ear and remove that excess flesh.
And yes, the ear would probably close up if you take it out. i went to zeros, and within a few weeks my ears shrank up to a normal ear piercing hole.