When to test?

We have a 2 year old already and he wasn’t planned! but we were very excited to find out! I had missed my period and that’s how I found out and took a test! Now we are trying for baby number 2 and I am finding it to be very hard to wait and test! We have been trying for 2 weeks on the 12th and I have 7 days till my next period! So when should I test?