Engaged?

I'm 16 (will be 17 this month)... I've been with my boyfriend for 2.5 years. We have a 8 month old daughter and I'm 20 weeks pregnant with our second daughter. (Please no hate, my birth control failed both times) We've been living together (our own place) for a year and half. We never argue, we are best friends. We financially support ourselves 100% ... my questions is, is it to soon to get engaged? He asked my father for his permission to marry me when I'm ready, and my dad said no. He does really like my boyfriend, except he finds I'm to young to be engaged and not ready... what do you think?