Women and weights

Don't be afraid of muscle gain, you're not going to look like a tank unless you start taking steroids. I'm also on the 'pocket sized' side of life and found doing weights gave my body a lovely toned/defined look that looked a lot stronger and healthier than the formally skinny/no tone look. If you're new to weights, you need to start light and focus on correct form. Light will vary from person to person though - start with 1kg, if its too easy then try increasing to 2kg, if its still too light try 3, etc. Generally, to gain muscle mass - higher weights, less reps. To build muscle endurance - lighter weights, more reps. If you cant maintain correct the form for every single rep though then the weights are too heavy. If you're new to weights it's much safer to start with lighter weights more reps while you build technique and endurance, and then start to increase weights, drop reps. I started with something like 3x20 or 3x15 (depending on exercise) and later went to 3x8 with higher weights. Good luck.