how far am I?

Helen
Hi all! Just found out we're pregnant! This will be our second baby. Soo freak in excited! Does anyone know a realiable app or website that can tell u how far along u are? I've downloaded 3 apps each telling me a different thing. Glow says I'm 3wks 5 days and Baby centre says I'm 4wks 4days. Mm a bit confusing! Thanks!