I have no issue whatsoever with backers getting earlier access to the game, this is standard practice.
However, it’d usually be something like $15 gets you the game, $20/25 gets you the game + beta access. This provides an incentive for people who want the game earlier to give you more money.
Really think about this. Who is that early tier even for? Do you often look at games in development and think “I’d really like to play a WIP version of this, but have no interest in a finished product.”? I bet you don’t. I bet nobody does.
The only purpose this tier will serve in practice is (probably unintentionally) tricking idiots into thinking they’re getting a full copy of your game for $7, which will obviously result in negative press / word of mouth.