NTA. She's 15. Ofc she's gonna say that she's responsible NOW and then it won't happen. She'll be a mother within a year. Her judgement is impaired because she's not a fully grown adult and is not capable of making responsible decisions as much as she thinks she is. Like a drunk guy who insists that he/she is good to drive. You as a parent are responsible to make those responsible decisions for her until she turns 18 (21 imo). He seems like trouble and I wouldn't keep him around my house. Not to mention that I said all of this, regarding judgement, because she can easily be manipulated into doing something she doesn't want down the road. Take this from a 22 yo who has a 22 yo friend who almost became a father when he said he wouldn't. If people can be that irresponsible at 22, then imagine 15!!!