I have one more game to play to get my rank. If I don't play it and wait until next season will my MMR "reset" or will I still be playing around the same elo I was playing with to determine my rank?

I'm fairly new and after i saw my friend struggle to rank up after he got placed in iron 2, i'm anxious if i'm good enough to play good to escape the low elo's. Is this normal and what should i do, should i play the placement matches or sho...