st. louis Missouri Nursing schools

Lutherin seems like a pretty good school to apply to. Its cheap, not far, and I can go from nothing to an RN quickly (2 years). Hopefully I get in this Fall.
Anyway I saw that they give "diplomas" not certificates. What's the difference?
If later on, I want to transfer to a university and finish the other two years, will it affect me?
Has anyone else attended Lutherin that has any advice?