At 120, I would suggest AP or ATA. I'm 125 and 5'5 and only had to cut off a little bit from the AP armour and another girl my size did the same with her ATA armour. There's certainly room to take off more for yourself. Very doable! But harder to find detailed tutorials. You'll want to look more into those armours to decide how long you want to wait, how much you want to pay, and which style you like better. To shorten the arms and legs you'll want to cut material off of the top and bottom of your arms and legs (near the armpit, wrist, ankles and near the crotch on the limbs) because the joint areas of the limbs have a more special shape that's harder to replicate. Lots of people will suggest making things thinner, but I might suggest using padding to make yourself look more bulky. Having one piece smaller makes it necessary to make every other piece smaller so that it looks in proportion. Keeping the width of the armour will also make you match other tks in your troop a little more closely. Good luck! And don't be discouraged!