TTC seeking insight/advice/thoughts please

Hello! Just downloaded the app tonight and so far I am loving it. I have a question: I already have an amazing 8 year old daughter and my hubby and I decided to have a baby :) yayy!! But, this is the thing.. we decided this about a year and a half ago and have been having unprotected sex since then but it's maybe once a week we can get it in (no pun intended) or whatever having an 8 year old allows because we are obviously appropriate. Do you think it has taken so long because of the lack of sex? Or that I haven't been tracking fertility times? Or both? I know obviously all it takes is having sex once and you can get pregnant but when you're actively trying, I feel like more sex and tracking fertility dates are very much needed. I conceived my daughter within a month of trying with her father so I didn't know if the second can take longer or having a C-Section may be affecting it. Sorry if it seems silly.. Just looking for thoughts/advice/insights.. Any of the above! Thank you :)