Hi there, welcome to the forum!
I had all my teeth out on the NHS, but I can't tell you exactly how it will be for you, as it's different for everyone. Are you worried about the extractions, or just the denture? Do you know if you're getting an immediate denture? That's a temporary one they use while your gums heal up and settle.
It'll be a process, and sometimes it might be frustrating. They cannot know for sure how your gums will look once they've healed, so initially there is some guesswork involved. You might find yourself, at points, with a denture that is not fitting properly, but they can adjust them endlessly, and they will.
Talking may be difficult at first, but you'd be amazed how quickly we humans adjust to new things. Your tongue will learn how to work around the new denture pretty fast, and soon you stop noticing it.
When I put a denture in for the first time, it felt pretty weird, I must say. My stomach thought that if there was a thing in my mouth, it must be food, and started getting all grumbly the way it does when I chew gum and my mouth started salivating like mad. This passes really quickly, and sucking on a sweet helps in the meantime!
I got to have input on how the teeth on my permanent one would look, so I imagine you will too. If you want them to look a lot like your teeth, try taking a picture of your grin and giving it to them. They can match colour if you want.
It's not the most fun process in the world, but it's not so bad either. Remember to stay positive. And there are some benefits - like not having to experience a dentist drill ever again!
If you have any specific questions at all, feel free to ask. You'll be fine.
