Hello , welcome to the forum. I'm 24 now and was diagnosed at 15 so I can relate strongly to your fears.
I agree with the others though, in general, surgery is a last resort and should only be done if medication doesn't work or if it's an emergency. If you start a medication and it doesn't work, you can stop it, but if you have but remove it doesn't grow back, it's a permanent thing and if you don't take medication to control or slow the inflammation it can keep returning, and you'd end up needing to keep having more and more gut removed .
The earlier you start having surgery, the more likely you are to need repeated operations, for example, I had surgery at 20, and have been told I have at least a 50% chance of needing another resection in the future. The more you have removed, the more at risk you are of needing a stoma, or of ending up with complications such as short bowel syndrome which can result in you needing to be fed through a drip (TPN) in severe cases. Even for relatively straightforward surgeries there can be life long consequences. I had a short section of my guy removed and have lost the ability to absorb B12 , so I will now be on injections for the rest of my life. Most people who have surgery are then put on medication to prevent the disease retuning anyway.
Another potential complication is adhesions, where parts of the gut stick together or get stuck to the stomach wall, these can cause symptoms including pain and sickness and in some cases result in bowel obstruction. They can also turn into fistulas, abnormal tracks between organs. Both of these complications can result in needing more surgery.
I'm not saying any of this to scare you, I just want to let you know that surgery shouldn't be taken lightly. It definitely has its place, I would probably have ended up with a perforation without it.
I understand the risks of the medication can be intimidating, especially when words like cancer are thrown into the mix, but the risks are actually quite low. The risk of getting cancer are only a few percent higher than the general population, and you are monitored extremely carefully to make sure that you aren't suffering unwanted effects. I have previously had inflectra and I'm now on vedolizumab. I did have an allergic reaction to inflectra (which can happen with anything ) but other than that I have had no other problems with either medication. I know many people who have been on biologics for years (longest I've heard is 7) and haven't had any complications , some even say they've transformed their lives.
As for steroids, these are for short term use only and if used correctly the chances of severe long term side effects are quite low.
The general consensus is that leaving Crohn's untreated or not using a strong enough treatment is far more serious than the risks of the medication side effects as in the worst scenario the complications of Crohn's can be fatal (this is rare though and usually happens if it's gone untreated for a long time) . If the doctors didn't believe it was the best treatment for you they wouldn't give you the option.
As for your concern about things getting worse, disease progression is different for everyone. There is a train of thought that says the more aggressive the drug treatment is during the early stages, the slower and less severe the progression.
If I'm honest, my pain seems worse now than it has been for a long time, but I have had a lot of trouble getting things under control, partly because I wasn't offered preventative treatment after my surgery and I now have inflammation in the area that was reconnected. If I had been offered medication it's likely I'd not been in such a bad position now.
Disease progression is very individual so it's not possible for us to say how yours will be going forward. There are cases where it actually gets better as people get older, so it's not necessarily going to get more painful. Many also find that each flare is different so your symptoms may change or be less obvious, this is particularly true if the inflammation is in a different part of the digestive tract.
