What happens in Final Fantasy VII if you decide not to get Yuffie?

okay...here's a hypothetical situation....for those who have played the game, i am sure u know that in order to get yuffie you have to find her in the forest, battle her and etc.....she then later on steals ur materia and you must run around wu-tai and get it all back....so my question: if you decide not to get yuffie, will the plot be affected?.....what happens if you decide not to get yuffie as a character during that period of time u are able to get her?....just a curious question....