What if you physically get up before taking BBT

My husband and I have a daughter, she'll be 4 in September. We've been wanting to have another child, with no luck. Iam a little underweight always have been cannot gain no matter what I do! I feel I may have a slight hormone imbalance which is causing it to tale so long to get pregnant. Im 33 hubby is 37. Instead of it possible taking another 4 yrs ( :( ) I purchased ovulation strips & a BBT. I keep forgetting to take my temp BEFORE I actually get up!! Can I still take it and get accurate read?