Not that many people can actually routinely go to the gym. (That's the business strategy gyms base their entire industry on) If you have even a tiny doubt that you can regularly go to a gym, don't waste your money on a membership. It's much more beneficial to try to find a trainer (and THEN get the membership), a group activity, etc than to just go buy a gym membership. I personally find it hard to motivate myself to work out on an individual level, but if I have a commitment to a group or trainer, I'm more likely to get my butt out of the house.
I'm doing an outdoor summer bootcamp right now. It's just a small group of 5 of us, plus the trainer who tells us what to do, yells encouragement, etc, and I HATE working out normally, but I'm actually excited to go to every session because I like having the support group and being outside.
It's a lifestyle change, but when you make the change, you feel a lot better about yourself.
Also, don't expect to look like a superhero in one summer
Guys like Amell, Evans, and Hemsworth spend months of working out every day with a personal trainer and strict dieting to get in shape for those characters. (And they're paid to do it! They don't go to the office or whatever like the rest of us and just work out before or after. It's their JOB to look like that)