8 months is not very long for a website to earn money online.
$20.00 is pretty good though for 8 months. Sometimes it can take a few years to gain enough traffic to increase your earnings and reach the $100.00 payment threshold.
Focus on creating more great content and then the money should follow.
Those earnings thousands per month with there website started there website decades ago.
Don't give up. If you create a great website with great content the website traffic should come in time and your earnings should increase.