How many steps should I learn a day on average?

I haven't seen any statistics for this.

But you could look at the profiles of several students near you on the weekly leaderboards and calculate an estimate from the dates on their achievement badges.

But since the courses are self-paced, I wouldn't put too much emphasis on average (or exceptional, for that matter) progress rates. Do as much as you have time for, and find enjoyable. Don't push yourself to meet some statistic if it seems taxing, and also don't withhold yourself if you feel inclined to do more.

Sometimes it is better to let the information soak in. Trying to be the fastest does not make you the best, or most valuable. That being said, it is always a good idea to push yourself a bit. However, in the end having real skill will bring value, and having value brings the job. (general comment)

Just have fun learning and mastering this stuff. Eventually, it will come. I come from a design background, and a professor once told me, "just keep at it and it will come." He was right and it did.

Now if you are just interested in understanding the data, I would contact support and see what numbers they have crunched. I to wondered about what a healthy daily does of work looks like.