iguanas are tricky. some are sweet as pie, others...not so much. i had a roommate one time who adopted an adult female iguana. supposedly she was very calm and settled at her previous home and my roommate even went there and handled her and checked her out before adopting her. when she came to live at our house...wow. she was SO mean. i think a lot of it was because she was afraid, but you couldn't even get near her without risk of being bitten or slapped with her giant tail (and boy does that sting when they get to slapping!) she had to be confined to my roommates room because when she came out into the rest of the house she was unmanageable--running, hissing, slapping, totally out of control. that experience drastically altered my perception of iguanas.

that said, i know there are iguanas out there that are calm and friendly and great pets. it's good that you have already had some experience with this iguana and that she seems friendly. realize that she may be nervous about a new environment and may act aggressively at first out of fear. i think that if my roommate had been more keen to her iguana's needs and less afraid of her she may have been able to work with her and calm her. surely this would have taken some time and would have been a challenge with a beast her size, but i think it may have been possible.