18 and want to get pregnant?!?!?!?

ok so im 18, have my life really sorted out. Been with the same guy for alittle over 2 years. He wants kids too, but we have decided to wait. I have the maternal feeling that i want to. I feel like i would do a great job, but i know i cant financially support a baby. basically could someone talk to me about it and help me understand why I shouldnt and such. or give me a website that would help me with this...ty inadvance I really appreciate it :D