Hi Betseyj,
First of all, welcome to the forums. While it's unfortunate that you're in a position that needs to bring you here, I'm glad you found us. This community and it's founder - Harrison - are an amazing bunch and very helpful.
In my opinion, your surgeons are right about it being a quality of life decision and that it's good to hold off for conservative measures if possible. That being said, if you are already in that much pain that you have to take pain meds to get through class, I would seriously consider the surgery sooner rather than later. Surgery like this is never ideal at such a young age, but I'm a big believer that if it's going to help your youth be more satisfying, do what needs to be done. The way I see it, other levels in my own spine will probably go eventually and I can patch/fix as needed with whatever new technologies exist. If I can't patch/fix in the future and suffer at that point, at least I've been able to enjoy my life relatively pain free through whatever point that may be.
I went through college avoiding most athletic activity because I'd always wind up in pain. One game of ultimate Frisbee with my friends would leave me gimpy for 2-3 days afterward. The saving grace I had was that if I avoided certain activities (running in particular) I could do most of what I wanted to do without being too disabled by the pain. Unfortunately, as my spine degenerated, the pain would increase and I would just become used to the pain. The pain was normal. That's never a good thing in my opinion.
Once I entered the work force, it just became more difficult to work with and ignore the pain. At one job, I told my supervisor and other superiors that lifting was going to sometime be a problem because I had back problems. I work in IT and was forced to lift giant printers on and off of shelves with no assistance. That job didn't last and I wound up in my current one. Eventually my spine just gave me a big ole "F U" and went while using the ladies room at work. After that, functioning at 100% at work became not only physically draining but mentally and emotionally draining as well.
I had known since I hurt my back in high school that I would probably need surgery someday. I never went to the doctor when I got hurt because I was stubborn and didn't want my mom to worry too bad like she was prone to doing. I started going to doctors for my back when I was 25 but got the run around by my primary care doc. He came to an incorrect diagnosis and wouldn't bother to consider anything else. I had to go after getting an MRI myself once my insurance through work changed to a point of service style plan. Thanks to a recommendation by my current awesome manager, I was able to find a top notch spine surgeon with my first visit and at a practice that caters to local athletes. Being athletic again was a big desire for me.
I had my surgery at the age of 27 and it was the best decision I ever made and I now wish I had gone to the doctor much much sooner. It may be buried now, but go take a look at my post-op thread. I only had L5-S1 done but I have degeneration starting at other levels so I know eventually I'll likely need more levels done. For now, they weren't bad enough to operate on and weren't pain generators, so the hope is that by putting in my Prodisc at L5-S1 it'll help preserve the other levels for as long as possible.
Personally, what I might try to do if I were in your situation, would be to time the surgery so that it doesn't disrupt your education but doesn't hold you back too far in terms of going out and finding a job. I'd likely do it after graduation during that student loan grace period. This way, you can enjoy the celebrations associated with graduating college and then give yourself plenty of time for recovery from surgery without worrying about whether or not your job will force you back to work too early. I got EXTREMELY lucky in that the folks I work for were very understanding and flexible with me and my recovery. Not all jobs will be as understanding, so it's definitely something to consider. As much as it stinks that you're facing surgery on your spine at your age, it may actually work in your favor. Not only will the post-college timing help, but age does too. That was another factor in my own surgical decision. I knew that the younger I faced surgery, the more likely I was to have a smooth recovery. I've actually been discussing the same with my mom as she's facing possible knee surgery after a skiing accident.
Anyway, I've babbled enough. Hopefully some of what I've said is helpful. Those who've had or are facing 2 level surgeries will likely chime in as well, but I figured since I think I'm one of the younger post-op folks here, my perspective might be helpful too.
Keep your chin up. Again, welcome and may you find all the help you need and then some while you're here.
~Sara