Everyone makes this mistake. It is rather the case that in English (and other languages) numerals are written right-to-left. You can tell since, when reading right-to-left, you will know exactly what each number signifies. If you start from the left, you will not know what the first number signifies until you have reached the end of the whole number.
Interesting to learn though that in Arabic it is still pronounced from left to right, up until the tens.