How soon to do the first ultrasound

Toya

So I found out a 8dpo retested and confirmed bfp at 11dpo had a tubal the middle of last year and really anxious to do and ultrasound to make sure this pregnancy is viable. According to some apps I'm 4wks 1 day others say 4wks others say 3wks 6days lol so I don't know which it is but I'm so nervous... any suggestions? (All are pregnancy test lol even doh the last to resemble ovulation test)