Reworking my "Former Twin" into my BFs Family (read)

I decided to cut out my Twin from my DR Family. Just have 2 Siblings is probally the right ammount + don't wanna share Birthdays etc. With a Twin when thininking more about it

I still kinda wanna use that "Tomboy Sister, Femboy Brother" Dynamic for my Boyfriend

But can't decide on Twin or ~1 Year Apart (with her being the older one)