Is an egocentric person stuck up?

Hello!

This question depends on what stage of development a person is in.

For example, young children are very egocentric. This means that they are unable to view the world through other peoples' eyes. However, this does not necessarily make them self-centered at this stage, because they are mentally incapable of understanding the feelings of others' at this point of development. 
For example, if a child wanted to give his grandmother a gift for her birthday, he may give her an action figure. This is not considered a selfish act, because he thought to give her a gift. However, the child's egocentrism causes him to get her a toy that he would like, since he is unable to understand what she would like. 

Later development, like a young adult for example, could be considered to be "stuck up." This is because at this stage, the person is capable of understanding other peoples' views, yet he chooses to make decisions that benefit him in particular. 

I hope this helps answer your question! Have a fantastic day!