For the first two days whenever I open the cage door she flies right out and goes on my shoulder but she would never step up on my finger no matter how much I try.
Have you tried finding out what her favorite treat is?
If you can find out what her favorite treat is, then you can try a little backwards training. Instead of asking her to step up, because she may not know how to step up, teach her to walk down your arm to your hand for a reward!
That is, she looks at your hand, reward. She moves her head towards your hand, reward. She takes a step towards your hand, reward. And slowly get her walking down your arm to your hand for said reward! Repeatedly rewarding her each step of the way! Then once on your hand, keep rewarding her for being there!
I stopped taking her out after those two days since I heard that even though she wants to come out, I should let her get used to my me first and get her to understand that if she wants to come out, she has to step up first.
I don't agree with this...
When I got Jayde, my red throated conure, she was 3 years old and both terrified of physical interaction and demanding it at the same time. It was so sad to see her beg for attention, but the moment I walked over to her, she'd run away in terror. I walk away, she'd attempt to follow without leaving her cage.
She used to be terrified of stepping onto hands, but would easily come off of her cage if she had direct access to my shoulder. I ended up teaching her that hands are "ok" by scritching her with one hand as I moved my other closer to her feet (while trying to avoid getting bitten!). Not only that, but I worked with her from stepping up to my shoulder from her cage, then my upper arm, then my elbow, then my lower arm, then my wrist.... slowly teaching her that hands don't need to be a scary thing!
If your bird wants to interact from day one, then let it! If it doesn't, that's ok, too! Work from the cage earning the birds trust! Instead of forcing Jayde out of her cage, I just wheeled her cage around the house so she could spend time with me without leaving the comfort of her cage! I even installed a perch on the outside of the cage so she could come sit near me but still be on her cage. I really think this helped a lot!
Now she doesnt seem to want to come out anymore won't step up either. I've been trying to put my finger near the door and hold a sunflower seed in the other hand and try to get her to come but she usually gets close and tries to reach with her beak.
If she's coming towards you, REWARD! Any behavior towards you should be rewarded! She doesn't have to touch you, she just needs to learn that you equals good things! And as she gets more comfortable with you, you can ask for more... i.e. standing even closer to you, touching you with a nail, touching you with two toes, putting a foot on you.... and finally, stepping up!
Break it down into tiny steps! Work with what she's willing to give you!
Although she's 7 months old, I half wonder if she wouldn't mind some warm, mushy foods... like steamed carrots and/or sweet potatoes. You can even add in some bananas or nut butter for extra flavor. Feed slightly warm.
Or maybe even try sharing healthy food with her, just don't feed her anything you've bitten off of!