Is it good to BD on your first fertile day?

Zoe • This is my first time ttc. 23 years old and have been married to my husband for almost 2 years now!
Hi everyone,
​I am TTC #1 and I have just entered my fertile window that glow calculated for me. Is it good to BD on my first fertile day? I also BD a couple of days before my fertile window, is that ok?
​Advise much appreciated!