There are no rules about gearing but you need to do some math as there are better ways to achieve your desired gearing. The chain ring size is one of three factors in determining your gearing, you need to factor in tire size and the rear cog size. Assuming you are running a 16 tooth cog and a 20 * 1.75 tire you are looking at 58.5 gear inches, if you have a 1.50 inch tire then it is 57.7 gear inches. There are gear charts all over the internet so you don't actually have to understand this.

Using a big chain ring is not terribly bright. By using a big chain ring you are increasing the weight of your chain ring and your chain as the chain needs to be longer. You would get exactly the same gear inches by using a 42 * 14.

In any event, anyone can push that gear, it is just not likely to be very efficient on most tracks.