Take a deep breath.
I'm 60 and my cancer sort of mirrors yours. Large mass in right ascending colon. It's scary. I'm 60 and this is my first brush with mortality. And you know what? It's not as scary once you accept that you have cancer. It's a concern, but it's far harder on my wife than it is for me. Why? Because I believe in my heart that I'm going to beat this monster. I'm sorry, I don't believe .. I KNOW!
First steps .. like others have said, don't go with a general surgeon. Sure, they can do it, but what you need right now - especially with a large mass - is a colorectal surgeon. Someone that does this type of surgery every day of the week. I'm lucky, I live near Dallas and we have a really good cancer center at UT Southwestern. One of the best in Texas. My surgeon is a surgical oncologist, and I also have a medical oncologist (for the chemo). The team approach will give you the best results.
Once you meet with a doctor (in my case, the first meeting was with the medical oncologist) he'll probably want a CT scan to have some kind of idea about what you're facing. Next, surgery. Surgery is going to happen, but you know what? Surgery is not scary at all. I was given a drug in pre-op and wheeled out to surgery. I don't remember ever arriving in surgery. All I remember is part of the ride and then being woke up in post-op. Very easy.
Recovery from surgery is next. Two suggestions that you'll find elsewhere on this forum .. walk, walk, walk, walk, walk .. and breathe into the little thing they'll give you. I spent 3 days and 2 nights in the hospital. And once home, I kept walking until I was so sore I could hardly walk. But it helped me recover very quickly.
Beyond that will depend on your particular case. But the best suggestion I can give, and others will agree, is to stay away from Dr. Google. It's easy to start checking statistics, etc, but those statistics are wrong for a number of reasons. First, a 5 year average is from people that had cancer diagnosed 5 years ago and more. Treatment has come a ways since then. And it will continue to improve over the next few years. Next, many of those did not receive treatment in a timely fashion. And many were not treated in a cancer center. All of that, plus other factors, skews the survival rates downward. So don't get caught up in that stuff. It'll make you very depressed.
I'm just finished my third round of chemo and it's not bad. I've had several CT scans and a PET scan. And I'm still here and I'm getting results from the chemo. Surgery later to remove tumors in my liver and lung. And possibly a bit more chemo. And then, if all the I's are dotted and T's crossed, plus the stars align correctly, I'll be cured. Or at least reach that plateau of No Evidence of Disease. That's the only results I will accept. Anything less is unacceptable.
So take another deep breath. You're just getting started and have quite a journey ahead of you. Go into it with the attitude that you can do this and you will survive. I believe I can beat it, and I believe you can beat it, too.
Hang in there. We're all in this together.
3/11/16 Colonoscopy - 9 benign polyps, 1 large cancerous tumor in right ascending colon
4/19/16 Right colectomy
6/3/16 Two liver spots detected, added Avastin to Folfox
12/20/16 Liver surgery. Pathology shows no active cancer cells
6/7/17 Final chemo
12/5/17 Port removed
05/23/18 Liver tumor discovered in scans
04/04/19 Radiation treatment
08/15/19 Additional radiation treatment
08/21/19 NED again