I want to know what it feels like to be a mother...

My Dad has always liked to say, “just wait until that biological clock starts ticking,” when I’ve refused to have kids and always said I didn’t want them etc. I’m turning 28 this month, and I’ve been with my current bf for more than 2 yrs now. He’s awesome and is there for me like no one else has ever been, though he’s on a high dose of Keppra for epilepsy etc. With him is the first time that I’ve ever considered having children of my own, bc I know how he’d care for them, and children would fill his days with joy, and we are actually partners who help each other, and watching my niece together, we’re awesome, etc. For more than a year now, I’ve been struggling with longing for my own child(-ren) with him, but I fear how his medicine may affect a pregnancy, and I don’t want a child out of wedlock, and we’re not ready for official marriage yet... I have an IUD, so it’s not going to happen until we’re ready, I trust, but I want it so bad I cry for it when I’m alone, I have dreams about it, and I get very angry about parents not treating their children right, among other things. I’m currently in grad school, so I figure it’s not the right time for me anyway, but then, is there ever a “right time” but when you’re ready for it? Should I just be patient, or should I discuss this further with my SO than just mentioning to him that I want it one day?