Bonni! This is wonderful!
First, I am so glad you did not feel that you had to conform to the technique I used in class and go to a particular world - our guides can go and be anywhere.
The fact that you were surprised by the bird appearing is one of the ways you can know you're not imagining or fabricating the information - we typically don't make up something that then surprises us. :)
As for the meaning or interpretation, its very important that you follow your intuition on this as well. There is so much wonderful information available about animal spirits, and much of it can be helpful, but what eagle means for one person can be entirely different for another. I suggest allowing what you experienced to sit lightly within you, and to stay open to further messages, insights, and wisdom about who this guide is for you and why they have appeared as eagle. This is the beginning of a relationship, so it will develop naturally as you spend more time with spirit.
The term 'spirit animal' (or 'power animal') means a guide or helper energy that is in animal form. It's widely believed by shamanic practitioners that spirit animals are the spirit of the entire species, not just an individual animal: in other words, that your spirit animal is not an individual eagle's spirit but is instead the Spirit of Eagle.
As a supportive note to others who may read this: all animal spirits - even mice, lizards, turtles, butterflies, squirrels and other small or 'gentle' creatures carry very big medicine and a great deal of power. You also may have more than one animal spirit in your life at any given time. 😊
I hope you keep us updated! 🦅