HELP REQUIRED.

HELLO ALL. JUST WANTED SOME EDVICE AND HELP ON RIGHT AMOUNT OF CALORIES AS THE WJOLE THING IS A LITTLE CONFUSING.

Im 5ft 5inch
weigh 177 pounds
and am 28 years old
i have a desk job but walk alot and got to the gym for 45 minuites 3 days a week.

I want to loose about 1lb a month and my overall goal is to loose 24lbs....
Ive set my diary to eat 1520 cals a day. does this seem right???

Also should i eat back my gym calories lost or not as i see a lot of conflicting advice on this. My diary is open if anyone wants to look. been on this a week so far and have lost 1lb which is my goal so think im doing ok just thought id check.

Many thanks in advance :)