Need advice and some peace of mind please 😭

Kalena • First time mother ☺️
I'm currently 15weeks and 4days pregnant. But I didn't find out I was pregnant until I was halfway through the 12week mark. So I haven't been taking my prenatal vitamins all that time. I didn't get to see my doctor till about 13 weeks and I was stupid and didn't think to take prenatal vitamins (this is my first pregnancy and no one told me anything) so I've only started taking them the past 2 weeks of being pregnant. So I'm wondering if that's going to hurt my baby and it's health at all? I've been healthy so there has been no complications really. But I just want to know other opinions.. 
Why are prenatals so important anyways? No negative comments please because I honestly don't know. I would ask my doctor but it's hard to get an appointment in with her and I'm not scheduled to see her again till the beginning of next month. Thanks ladies 💕