Trying to lose weight

Mrs • I`m 33 w/3 daughters & a 1 son.. I have been w/my husband 15 yrs, but only been married 5 yrs
What's a good diet? I'm really picky eater. I don't eat salad or most green vegetables. But I have gain like 15 lbs since I've gotten married a year ago & I'm still gaining. I started walking last week & trying to drink more water. But what's a fast way to lose it? I'm scared of diet pills I don't wanna look sick after I lose. But I do want to lose & lose fast. At least 20 lbs. I'm 5'6 & I weigh 163. Can someone help me?