The thing nobody tells you about a green top is that it doesn't fade the way other colours do. It goes a bit flat and a bit grey around the collar first, long before the rest of it gives up, so you end up with a top that still looks fine from a distance in a photo but looks tired the second you're close enough to see the neckline properly. That's the tell I check for now before anything else.
Some greens are just easier to live with than others. A deep bottle or forest shade behaves itself near every skin tone and doesn't date the way a bright emerald or a khaki with too much yellow in it can, those two go in and out of looking right within a couple of years. Olive is the safest starting point if green feels like a risk, it sits closer to neutral than people expect and it won't fight with navy, camel or black, which is most of what's already hanging up. The difference between a good one and a disappointing one usually comes down to the fabric doing what it's told. Cheap green tops are often dyed on a thinner cotton or a viscose blend that goes see through under shop lighting that's doing it favours, then looks completely different once you're stood under a normal bulb at home. Press the fabric between your fingers before you buy it. If you can see daylight through it stretched over your hand, it'll be worse after a wash, not better. Check the stitching at the shoulder seams too, that's where a cheap top gives itself away first, puckering after one wash even if the colour holds. Hardware matters less here than with other tops, but if there's a button placket or a tie at the neck, give it a proper tug, flimsy green cotton with a loose button is a top you'll be sewing back together by week three.
A plain crew neck or round neck in a mid to deep green is the one to buy first if you've got nothing in the colour at all, it layers under jumpers in fit autumn and works on its own come warmer weather without ever looking like it's trying too hard. In the shop, hold it up against your own skin rather than trusting the model, green is one of those colours that can look completely different ten centimetres from your face than it does on a hanger three feet away under fluorescent light.
I didn't wear green for years because one bad khaki top convinced me the whole colour was against me, and that was just a bad khaki.