I am a front end developer with 2 years experience, I am new to agile and I am having difficulty doing estimates to for user stories since I don't have any design for it? I am not sure how can I give estimate without even seeing a wire-frame and just by user story definition? We are following scrum as I have been told. I even asked my lead that how much does estimates depend on the design and both web and mobile gave me the answer 95%. But our manager said it can be done, so is there a way to give estimation without design?
Is it allowed to be revisited at a later time? What happens when I realize that the particular user story UI has a lot of animation and flashy stuff that throws out my estimation, is it recommended that I change my estimation on user story or to better phrase the question as a developer, how can I better inform team that my estimation of the complexity of the work changed in light of new info and it will affect the sprint?
I realize that creating UI first then building API and Front-End is not how agile works so I am assuming front-end does need to estimate before any design