TTC #1's perspective

So I'm trying to conceive #1 and I'm wanting to give my perspective but also want to understand others perspective. Glow seems to be the best place to ask. 
​For me, the biggest struggle in trying to conceive #1 is wondering if I can have children... Since I've never been pregnant before. I've given up any deadlines (and have grown content with enjoying life)while ttc. But I'm slightly concerned IF I can have kids.
​    Do any other ttc #1 women feel that this is (one of) the hardest part? We ALL have dreams and expectations that are valid (ie when, how many, spacing etc) However, this leads up to my second question, "Why do a lot of moms (who want more) become very anxious about conceiving again? Again, wanting more children is great but I'm wondering why there's not a more relaxed approach the next time around (since they are able to hold their precious baby)? Just wondering.