I don't know if this helps, but I go on my actual size over weight, as people lose weight and lose different amounts on their body. So get a cheap tape measure and keep say a weekly log. I'll let you know what I measure:
Bust
Waist
Hips
Biggest part of thigh
Biggest part of arm
You can track your weight loss easier that way, or I think you do.
Plus take a photo of your face & body (with say knickers & bra) as you lose weight it'll be visible and it'll be motivation. Wilko's do a journal/diary where it's not got dates so you can keep a track that way.
It's a lifestyle choice, you'll be so proud of yourself. It doesn't have to be dull and boring.
I don't know how you feel about it but I really enjoyed watching Mama June on her honest journey. I know she had surgery, but she had to adjust her diet and exercise regime.
My weight is like a yoyo, so you can never guess which way it'll go. I've got a wardrobe with clothes size 6 to 18.
I haven't RTFT, but I've got hypothyroidism & type 2 diabetes, that causes issues when losing weight.
Vitamin B Complex is good to help boost metabolism, Korean Ginseng too. Vitamin D6 helps as we're usually deficient in it.
Minor changes to your diet can have a big effect.