Tension with parents

Okay so really need advice from any moms out there with older kids. I’m about halfway through college and have had a lot of up and down tension with my stepmom and dad. They really encourage me to grow in my relationship with Christ and I appreciate that. However, there are times like recently that they push me to put school and work FIRST. And this semester God has really been pushing me a little out of my comfort zone and calling me on a mission trip this spring break. My parents are NOT happy about this because they say I’m being dishonoring breaking this agreement we have written down. The agreement says about spring break that I have to have a certain GPA overall and made good choices in the past several months. But the disconnect is that we had a different view on this and didn’t realize until now. I was on the side of having good grades overall by the time spring break was here and my semester has been off to a great start. I don’t see why my past decisions should hold me back from doing the Lord’s work. His will comes before everything and everyone + this mission trip is not interfering with school and I’ve raised 97% of the money through several ways (by God’s provision. They don’t think it’s His timing and the big thing is breaking this “contract” (it really is a contract w them) and that God wouldn’t ask me to dishonor them... I think the issue is perspective and distrust from my past decisions. I understand where they are coming from but confused that they don’t think this is me putting God first and what HE is asking me to do.. but I am 100% confident after lots of prayer. I just want insight on what you opinions are. I fully trust and believe that I am making the decision God wants, it’s just difficult that my parents are so upset with me about this...