Question ladies

So I'm 20 years old about to be 21 next month. Currently trying for baby #1 and been trying for 8 months or 9 months. I've been using opks, I have 2 different apps. My cycles varies around 32 days is what the calculator came up as. This cycle, I wanna try to get a birthday surprise! So if you have any tips for me to try out. Please let me know. I am pretty much in good shape, I am employed so I get my exercise everyday. I get good amount of sleep. I just have a feeling we have sex to much so maybe the sperm isn't fertile and I'm missing my chance. Please help me when to start testing I'm using these opks. And here is my cycles from <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> and Premom app. And which days should I have sex. Trying to limit the days we have sex so maybe the sperm will be fertile from my fiance. Thank you for the help!!! Last month fully trying before obgyn appt in January.