I'm really sorry about your situation. I think it's completely unfair.
I have a 9 year old nephew who is also in a wheelchair as he was born with Cerebal Palsy (meaning, basically, he can't walk but he is not affected at all mentally) and it really hurts me to think that just because you too are bound to a chair that you can't marry the one person you love. It also makes me really angry.
A verse I can use for, hopefully, encouragement as you try and figure out what's best for you is from, of course, 1 Corinthians 13.
"Love is patient, love it kind...it is not easily angered, it keeps no record of wrongs...it always protects, always trusts, always hopes, always perseveres. Love never fails."
I see two types of love in that passage relating to your situation; the love for your partner and your love for Christ.
With you relationship with Christ, in this situation, you need to trust that He knows why He has put this obstacle in front of you, to persevere in your love for your partner and in prayer and to be patient while He fulfills His plan for you.
With your partner, I can see how her parents believe you need to look after her but really, is it necessary? Why do you need to protect her physically? It's nothing but Biblical for the husband to be the spiritual leader for his wife and family and regardless with your ability to walk, you are able to fulfill your role spiritually. It's not a Biblical standard that you need to be of full health in order to physically protect your wife. That is not an issue at all. What matters is spiritual health and that you're leading her.
Colossions 3:18-21 states a guidance for a Biblical household, as does Ephesians 5:22-33 It mentions nothing about physical appearance! A godly household is built upon a strong faith, in which you will be more than capable of pursuing!
I hope you express your disappointment to her parents because it is completely unfair. If I was in your position, I'd express how you felt but I'd honestly, still continue on with your wedding and wish that they'd support you. You're not doing anything against God or His Biblical standards! You do, however, need to pray about if God is using this circumstance to tell you if this person is not "the one" so you are not going against His will. I know you don't want to upset people close to you, but if you're not feeling any convictions from the Lord, then till death till you both part, in my eyes =)
Good luck bro, praying for you!!
I'm afraid of posting anything because you are older than me and I don't know if I have the right to.
