i sold my car and did my CBT and got a 50cc a year before my daughter was born to save some cash.
i would rather cut off a limb than go anywhere near a motorbike again, i didnt really enjoy it at all.
you are totally invisible to car drivers, lucky i only did a 8 mile round commute which was enough. you can be the best biker in the world but it means jack sh*t if an idiot pulls out of a junction and doesnt see you.
The CBT imo it does not prepare you for the road, looking back i think only certain people with bigger balls than me can be competent riders.
i see learners out on the road now and cringe.
only advice i can give is dont buy cheap, get a good helmet and good boots, gloves, coat.
if you like it i would save yup and do your full test a.s.a.p
good luck!