My off-hand thoughts: Meeting their physical needs (very large space, part humid, part dry, & proper heat), keeping it clean (think about the output of a large active creature that's probably going to run thru stuff, ahem), plus the challenge of handling the animal itself. They climb, they dig, & they can live 15-20 years. I've read they need substrate that's at least a foot deep, & that's not going to be easy or cheap to replace in such a large tank/enclosure, while not keeping it clean enough is a recipe for a sick lizard.
Consider the high cost of both the animal & all it's needs for life, including exotic vet care. Their most likely health issues are MBD, parasites (from wild food sources), & obesity (preventable). Try to consider where you'll be in 5 or 10 years- will you still want this animal in your life or will it interfere with other plans you have, including interpersonal/social plans. As an intelligent lizard, they're said to need a fair amount of mental stimulation to avoid self-destructive behaviors (like nose-rubbing etc.)- so consider how much time you have also.
I'd read ALL the "care" sources you can find because they don't all mention the same things in just the same way, & try to read between the lines. And if you can find & talk to some with experience, by all means do that. Only you know what you'll be happy with- and what fits your life, your budget, & all your future plans. The right pets enrich our lives- the wrong ones sadly become a burden.