Here is an interesting article on tattooing written from a Christian perspective.
I'd add one more reason to the 7 he already gives: tattoos are trashy, especially big ones and especially on women. The reason they are so popular nowadays is that our society and culture are going down the drain as reflected in our fashions and our entertainment. Not so long ago the only females who would decorate themselves with tattoos were prostitutes and/or those belonging to the criminal underclass. Outside of hipster circles it's still mostly lower class phenomenon.
Please don't do it!