The truck Georgie is shown driving is the same one his dad, George Sr, drove in Young Sheldon. You can recognize the stickers in the rear window.
Mandy is 11 years older than Georgie, in real life Emily Osment is 11 years older than Montana Jordan.
Montana Jordan and Lance Barber are the only actors that have appeared in The Big Bang Theory (2007), Young Sheldon (2017), and George And Mandy's First Marriage.
This is a sequel series to Young Sheldon (2017), which is a prequel series of The Big Bang Theory (2007).