i suggest you read this
it has sources and such
i even quote the relevant part for you:
New accounts
If a player has never played competitive, his initial competitive SR is around 2350 (38). For new players, MMR and SR are more volatile (35) and SR has been measured to approximately follow the formula: SR change = -3.85 * game + 99.34 (38) until about game 18. So even though everyone starts around 2350, after 18 matches, there is a wide variation in ratings. To fall to the depths of bronze, or climb the highs of top 500, requires significantly more games, however. That is, newer accounts tend to be artificially close to high gold.
there is also this post with a ton of research behind it Initial Competitive Skill Rating, Decrypted
and Jeff Kaplan himself stating that qp and comp have seperate MMR
but fine, ignore all that because a heavily edited video shows a quote from the forums and someone going 8-2 and placing in gold