Welcome, and congrats.
Keep in mind that moving in is a huge leap. You have to consider everything, not just romance and feelings. The added stress of higher utilities, food, etc mixed with the stress of rent if someone misses a payment is a factor. You've also got personality types (Type A, slobs, etc) to consider. Six months is a long time to learn all of this, but I would do some partial living first just to make sure you all mesh. Especially with someone else joining the fold. If you and Mr. X don't get along, that will be bad.
Assuming none of the above is an issue then move forward and be happy! Lucky ducky!
"Regret for the things we did can be tempered by time; it is the regret for the things we did not do that is inconsolable." - Sydney Smith
Kyle: 27 year old male
Katie (rymmare): 25 year old female
Kids: girl: 5 years old, boy: 3 years old