First ultrasound appointment!

I'm pregnant with my second child and I go in on Friday for an ultrasound. I'm so curious to know how far along I am since I've been off of birth control since August but have been breastfeeding my toddler. I haven't had a period since she was born (she's now 18 months) so I have zero idea how long I've been pregnant for. I just had a hunch last week that something wasn't quite right so I took 2 tests and they both came back positive! I'm so nervous and excited! Has anyone else been in a similar situation?