Make sure that the habitat, enclosure or cage the iguana will be living in is big enough before you relinquish the iguana. If the prospective adopter wants to allow the iguana to free roam, make sure they understand the risks, particularly in a part of the country where it gets cold and it is hard to heat an entire house to the appropriate temperatures. This is in addition to the time spent buying food, cleaning cages, preparing food, etc. An iguana owner should be willing to make the effort to find a good vet for the iguana, even if it means driving for an hour to get there. If the prospective adopter doesn't feel a vet is necessary, then you may want to reconsider this person.
Iguanas are expensive.
If the prospective adopter seems to be reluctant to pay for the basic need of the iguana, then they may not be a good person to adopt to. Experience helps, of course. However, do not turn down a prospective adopter because they do not have prior experience. Someone who has researched iguanas, spent time with them, understands the needs and the care involved, can make a very good owner even if they have never had one before. It just depends on the feeling you get from the adopter.