Hai I am 21 years old.. iam a little over weight and I want to reduce my belly.. thoght of skipping rope.. but people advised not to as it will affect the uterus.. is it true? Please help me..

No that is not true. Skipping rope is a great aerobic exercise.

Skipping rope is an awesome way to loose a few pounds and will not affect your uterus in any way! Other great exercises for slimming down are bike riding, running (or using an eliptical if your not quite ready for running) and, walking. For around your stomach area a good way to loose weight is to do sit ups and core exercises. It might be hard at first but if you do a little bit every day it makes a real difference. A good website for beginner sit-uper's is the 200 sit-up challenge, you start doing just a few and work your way up to 200 at a time; they have other challenges as well: http://www.twohundredsitups.com/
Mapmyrun.com is also a good way to track fitness levels and can help you set goals (even if they don't include running). It also has a section where you can chart what you're eating so you can look back and see how many calories you burned from your daily intake.

Normal exercise will not hurt your uterus at all, but if you don't feel comfortable doing something try another exercise there are plenty out there!