Romeo, time to start the ball rolling for a power wheelchair. When you start to lose core strength, it can go quickly. A higher cushion just for the sake of getting up, reduces your back support, changes the center of gravity and creates more skin/circulatory risk. Unless a caregiver can safely and reliably bear your full weight, trying to pop up using your arms for impetus (which could also dislocate your shoulder(s)) is a recipe for caregiver injury and/or your falling.
Bear in mind many PALS with early trunk weakness do not use a manual wheelchair for any length of time, if at all, for some of the reasons I have mentioned.
When you still have some ability to assist with standing, a power chair with anterior tilt can really help and will have other uses when you can no longer help.
Best,
Laurie