I don't think anything can prepare you for the amount of commitment and high maintenance of ANY bird but we all do and we all manage. I think there are many factors to be considered such as how well you think you would be able to cope with behavioural difficulties, health, diet and the day to day constraints, even if you can afford the best money can buy and source what you need it doesn't mean it will make a happy parrot. For instance, pellet conversion can be one of the most time consuming and thankless tasks.
I don't think there's anything wrong with getting a rescue and this African Grey sounds healthy however it would need a complete new bird work up by an avian vet and 6 monthly check ups there after. Its possible that in the distress of moving to a new home the bird may require re-taming and training.
I've never owned an African Grey personally but I am very close to several people who have. All birds are time consuming and expensive to look after but African Grey's, along with toos', macaws and larger parrots are extremely so.
I'm sure you've thought this through well, but I'm just preparing you for what may or may not ensue. The intelligence of these birds can cause problems, such as escape, destruction, boredom (which can lead to another of issues). This will be a lifelong commitment.
I would also recommend keeping the bird flighted, unless there is a medical reason for the bird to be clipped, let your bird be flighted and adapt the behaviour around them.
I really hope that this bird finds a nice home with you and I'm glad you heed everyone's advice and have seeked out help well

Good Luck.