Signs of being truly ready to wean are;
being able to sit upright (its not exactly great to eat lying down) not necessarily unaided, but pretty upright so food can be easily swallowed.
Being able to get food quickly and accurately to their mouth. - this is not the same as chewing on everything, babies do that to learn.
Making chewing motions.
For most kids these appear around 6months ish. My Dd1 was 4.5 though, so are earlier.
17 weeks really is the absolute earliest you should wean as LOs gut is not mature enough before that, earlier increases risk of allergies, ibs etc.
Contrary to what you may here - waking in the night is NOT a sign to wean (4 month sleep regression is very common!!) solids will NOT make your baby sleep longer/better etc.
And an increase in milk intake is most likely due to a growth spurt, not wanting food. BM/formula are higher in calories than what ur LO will eat when you start weaning .