Help 15 year old Alexis get a custom wheelchair

I am 15 and I have postural orthostatic tachycardia syndrome, also known as POTS, as well as hyper mobility, neuropathy and more. I am looking to get a custom wheelchair so that I can go on outings without overdoing it and hurting my body. I am starting at a new school this fall, this school does educational outings, and for me to fully participate I need a wheelchair, especially when it comes to walking long distances. I can walk for a while but it causes me extreme pain and puts extra stress on my body. Any donations would be used to cover the expenses of the wheelchair.