1st run - 4.25G - 17 ~ 1.070 Preboil -
Based on boiling 12.35 gallonsliters at 1.040 for 90 minutes, this will decrease your wort by 1.50 gallonsliters, bringing your after boil OG to 1.045. You were planning on an OG of 1.045 so you are right on track. Nice job!