Do you remember the old saying "you cannot teach an old dog new tricks"? That is about as false to dogs as it is to iguanas. I have a rescue that is probably 10 years old, she was mean and not wanting to be in a new home. She is quite good at tail whipping and did not trust a single person.
When we first picked her up and brought her home it was a big change for her. She was abused, had some scars and missing toe nails, her color was just black. I spent a few weeks getting her to trust me that I would feed her regularly on a schedule, I started with food in a bowl, then food being place in front of her, by the end of the month she only wanted to eat out of my hand. If I did not stick around and hand her food, she would not eat right away and she would give me bad looks. She was a princess and wanted her attention.
So she started to trust me, but I was NOT allowed to touch her, this took some major work. I started by slowly placing my hand near her without touching, took a few tail whips, but I did not move my hand. Within a few weeks of doing this, I was able to touch her gently on her lobes and scratch her belly. Here we are a year later, I cannot hold her, BUT she will sit on my shoulders and allow me to steady her from falling. She still wants to eat out of my hand, I can still scratch her belly, and I can get as close to her as I want without getting a mouthful of tail.
Her nails are growing back, her scars are well healed, and she is a beautiful green.
Give the iguana time, soon enough she will come around to you and get excited when she sees you.