Lizzie here's something yo make you feel better...your 5"5 and 9stone 8lbs...well I'm 4"11 & just over 9stone...so don't let numbers get you down.
I've been freaking out about my appearance too & as we get older it gets harder so don't be disheartened if you don't see the weight falling off straight away!
Drink loads of water, at least 2L a day...you'll find this will start to clean you out. I know we're not all the same but water is the cure to a lot of things. I despise drinking boring water but since drinking 2L a day I go to the loo at least 3-4 times a day & feel much lighter for it.
They say when you work out your heart rate needs to be kinda high for your body to actually start working off excess weight so build up your cardio. Zumba is good but more fun than anything...trying jogging or skipping.
Lunges will help boost that booty...lol.
Eat well & only eat what you can handle...I say this cos my major problem was over-eating & literally feeling my stomach expand...my eyes are bigger than my belly
'Youtube' stomach toning exercises & stuff...
Notice I haven't mentioned the gym!!! Hey maybe I'm not the best to offer advice...ha ha.
Honestly though simple things can help you achieve what you want...taking the stairs instead of the lift, holding your stomach in & pushing your bottom out when your walking (may not help to lose weight but will make you feel damn good)
Get some light weights to use when your watching tv or waiting for your rice to boil in the kitchen...hold your stomach in & do some stomach crunches or something.
Ok I'm starting to babble & give away ALL my crazy tactics to, what I think, will help achieve a nice body.
Good luck hunny