Is this fine or do I need to learn typing with 10 fingers?
A typing speed of 75 WPM is excellent. Most people have an average of 40 WPM. But I would suggest it would be better to practice touch typing.
Touch typing is the method of typing that you use all your fingers and type without looking at the keyboard because you are already familiar with the keys.This might help your speed increase a little more.
Community Moderator at Typesy