Male or Female ?

[Fish4Life]

Greetings!
2 weeks ago I received an apisto cockatoo in a really bad shape with white fungus on it's mouth and ich from someone working at a store , decided to take him/her and give it a second chance.
Well long story short it recovered quite fast looking good but...
I just can't determine the gender of it!
•Noticed some times it becomes a bit territorial
•Size is about 3,5 cm
•A lot of times her color changes to a gold/yellow very bright especially the pelvic fins (which makes me believe she might be a female..?)
Active and heathy would like to get him/her a mate.
Here are some photos of it:

Can provide more images if needed.

 

[Mike Wise]

At the size it is now, it could be either a female or a young male. In a month or 2 its sex should be more obvious.

 

[Fish4Life]

At the size it is now, it could be either a female or a young male. In a month or 2 its sex should be more obvious.

I see , thank you !