unless you're like bunnies - then, you will probably fall pregnant quite quickly.
for you
You need to find out the length of your follicular phase and as BritAcrossSea advised, the best method is temping - if you partner this with monitoring your CM - it can provide you with a better idea. I ovulate on day 12 of my cycle, so I am have a short FP, with a 15 day LP - everyone is different - if you take the average, you could miss your fertile window - unless you're like bunnies - then, you will probably fall pregnant quite quickly.
for you