Little bit of help please!

According to this site [here]  
At 18, 5ft 3 and 113lbs, i need to walk up to 9,400 steps a day to be classed as 'somewhat active' were i will then need 1934.0 kcal to maintain my weight. As i do 20minutes of Circuit Training every morning that then brings my maintenance allowance to 2089.0 kcal. I know at the moment im nowhere near classed as 'somewhat active' because i only walk around 3,000 steps a day.

I would really like to follow these guidelines but would like some input before i do so. The site does specifically mention "These recommendations are specific to girls between the ages of 14 and 18"

Last time i walked 10,000 steps i was on a deficit eating 1300 a day and ended up burning muscle, is there any risks if im eating back my calories this time around? Also im trying to boost my metabolism, is this the way to go?

Anyone?

It's similar to this site  http://www.bcm.edu/cnrc/bodycomp/bmiz2.html  and, if  you enter your stats you'll find it also recommends 1940 for a 'light' level of activity... which you'd class as.  Rising to 2240 if your activity increases to more than half an hour.

These calculations are only ever a best guess.  The proof of the pudding is in the eating, of course.  If you went with 1900-2000 a day and found you were losing weight then you'd increase your intake..... common sense.  If your weight stays roughly the same, then it's the right amount.

I'm taking it that, at your current weight, you didn't have any plans to lose any......?  No need.

No im not planning to lose weight, i would like to get in shape a little more hopefully the circuit training will help me with that. So im understanding this right i should target the 9400 steps?