like alaysha said it really depends, every pregnancy and woman are different. i started feeling things regularly at 18-19 weeks and this is my first pregnancy but alot of woman for first pregnancies wont feel anything until past 20 weeks. they say if you are thinner that you may feel it sooner but i'm not sure how accurate that is. it will happen trust me =] i felt like i waited for ever and now i'm 24 weeks and am getting the c$ap kicked outta me all the time haha
Well it depends on a lot of factors such as where the baby is positioned, if you uterus is even slightly tilted it could make it take longer, etc. Usual time frame for first pregnancies though are 18-22 weeks for those first kicks.