Why do I play with Gold Nova when It's my second competive play?

As a starter I already play with people from Gold Nova. What I hate because I'm really bad and have no idea what I'm doing. Im unranked but as a starter, shouldn't you play with silvers?

When you are unranked it is hard for a game to determine you level of play. So your very first competetive game will usually put you a bit higher then what might actually be your level of skill, as you could be on a alternate account or have played previous games. The more you play the better of an idea the game gets of what your level of skill is. Same goes for games like League of Legends, Rocket League, Dota2 etc.

This is usually done in the form of MMR (a common term for matchmaking rating). So as you lose some games (which is too much to worry about as you just started), it shall lower the MMR, which means you will be playing against lower ranked players. If you win, the MMR will increase, pairing you with higher level players.

Another factor to keep in mind is that when you queue with friends who have a high MMR or have a rank already, you will face tougher opponents since it takes into account the MMR of your teammates to make a balanced game.

Edit

in some games, if you queue with friends you will also get an additional 'penalty' to the team MMR meaning you would match against higher players

TL;DR: The system doesn't know your exact level of skill (MMR). This will be adjusted the more you play (lowers on losses, increases on wins). It does take in account your teammates' and friends' MMR when queued, so that could also explain the matchmaking