Surely by "boyfriend" you mean your future spouse, right? At least you're planning to marry soon and have kids, are you not? If you feel he is really THE ONE for you, more than just a momentary bonding tool, more than a quick hookup, then you should get on it as soon as possible. Announcing long term plans is important early on in a relationship, making sure you aren't setting yourselves up for a disappointment and bunch of wasted time later on.
If you feel truly comfortable with him and vice versa, for the benefit of both, you should propose immediately before another girl snatches him from you. There is a growing chance every day and the closer you two become, the worse it hurts when/if breakup happens.
On imageboards and reddit you sometimes hear comments like "reproduction is a modern jewish scam", "it would be immoral to bring more people to suffer on this planet", "having kids removes your independence and freedom" and other such mumbo jumbo. This is a coping pattern and these people are already in misery and without purpose, because they're too afraid (or not ready yet) to begin playing the game.
The unfortunate truth is, there WILL eventually be a time in your life when you begin to feel like you should('ve) had kids, and after you bypass that point no amount of "mindfulness" or self-help literature will cure the mental anguish which manifests when one has failed to fulfill their biological duty. This goes for guys as well.