My girlfriend told me she wanted to have my babies?

Me and my girlfriend were on a date and we were kissing not making out and we plan on getting married when were 18 she has a promise ring and she's 14 and Im 15 and she wants me too get her pregnant now and I love kids and I think Id make a great father and Yes I have a job and make good grades.... I save money and I can take care of myself I never get in trouble and stay away from drugs and per pressure and so I kind of want this baby but I want advice before I even do have sex with her so and advice would be usefull thanks :)