MMR at pre lvl 30, does it effect rank promos?

So I created this account yesterday, been playing on it a bit. I started playing league in late s1 and currently hold an account in gold3. I'm wondering how mmr works on new accounts (like this one) and would it effect ranked promos when you reach lvl 30. I noticed that in past games i'm having on this account i'm getting matched with players who are more mechanically inclined than my gold account and I'm wondering how that is possible. and would the blind/draft pick mmr effect your tier after promos seeing as this account has not seen a previous ranked season. xD thanks