I feel like my dad knows about my gender, but I'm afraid I'm wrong

I already dress masculine and bind and refer to myself as a guy a lot of the time (if not, then at least use gender neutral things- for example, calling myself a "teenager" instead of a teenage girl) just sort of out in the open to my dad. We've discussed the way I dress before, and he buys me guy clothes and doesn't question when I take him to the guy's section at stores when it's time to buy new clothes of some kind. However I've never OFFICIALLY come out to my dad as FtM- I know he'll accept me, thankfully, because we've discussed some of my transgender friends and I even had a transguy boyfriend once and he was totally accepting and okay. However, it's happened before where I thought something was blatantly obvious to him when it actually came as a surprise- I don't want to make the same mistake twice. Granted the circumstances are a bit different now due to the fact that well, I already dress to match my gender almost every day (I can't bind every single day because it messes with my ribs) and he's seen my friends referring to me by a different name. My dad is really important to me, and I sort of attribute him to why I'm comfortable with my gender identity now even if he doesn't know yet- he let me go fishing and golfing with him when I was younger, didn't refuse to buy me guy's clothes, never really questioned or condemned any of the stuff I did relating to gender presentation. I even decided that, when I change my name, his middle name will be a part of my first name as tribute. He's so important to me that I REALLY don't wanna mess this up- do you guys have any tips on things that I should do or say when I talk to him? He's a worrying type and freaks out a lot over things and I don't wanna make him sad or anything