I am shoe size 6.5, but there are a pair of soccer cleats that i really like that are 7, will they big too big?

If you are using them for soccer (or football, as we British people call it), then no, as you will probably also be wearing soccer (or football) socks. If you are referring to cleats as in the studs on the outside of the shoe, then they will probably not fit because they will be designed to fit the same shoe size they have been allocated.