Hot Mamas are great for first timers. My first wrap was a Hot Mama. She offers very unique and beautiful designs. Here is some more info:
http://hyenacart.com/momandmecreations/
Use discount code "ten" minus quotes to get $10 off your purchase. This code is good for all instock wraps and pouches ONLY. It does not apply to pads or T shirts.
Sale ends Friday, 2/17, at 10pm PST.
I am also 5'0" and about 110lbs. I can use a 3.7m for all carries, but I would probably recommend a 4.2m size for your SIL. Good luck!
Blythe
Mom to Luke & Karli
Searching for Jonas (true size 5 or small size 6)...I promise to give him a good home.