Not sure how far along I am in my pregnancy. Please help me calculate.

Hi all.

I found out I was pregnant a few days ago but I'm a little confused on how far along I actually am In the pregnancy. The first day of my last period was 9/27/17. My ovulation period was from 10/6/17 until 10/12/17. We conceived either on the 7th or 8th of October.

The thing which confused me was I used the clear blue pregnancy test and weeks indicator which said 'pregnant 3+'.

According to the website, this means that I'm 5 weeks pregnant or over. Would this be correct? Apparently it's 93% accurate in determining how far along you are. But how can this be if I began my period 4 weeks ago?

I will be going to get my first scan in a couple of weeks but just thought I'd reach out to see if anyone could help me understand all this.