Too much character development too soon?
 

I'm 25 pages into my novel. The subplot is enemies-to-lovers. There has already been a three month time-skip, and my LI has sorta apologized for some of his bad behavior to the MC, then (jokingly) threaten her life.

Is the apology taking stuff too quickly? I want them to have an established relationship about half-way to three-forth's of the way through the book, and I'm about a fifth of the way through.

The Subplot helps kick start the main plot, so that's why I'm not sure if I'm going too fast.

Here's my plot roller coaster to get an idea:

https://qoghrg.by3302.livefilestore....er3.png?psid=1

Spoilers (I guess???)
Basically what happens is the LI and MC starting a serious relationship is what causes the Third Party to get mad and kidnap MC's baby brother, which leads to the MAIN plot.

Sometimes things don't go as plan.
If you are doing NaNo trying to achieve 50k in a month, and not faring well, I would suggest you to not think about it but let it flow, write it out. When you came to the end, you may realize that your subplot is not too early but too late to start. After you finish the first draft, then you have a much better idea how you want to weigh your plot importance. Whether is that MAIN plot is as main/interesting as you first plan? That is where editing comes from.

And if you are doing well with word count and have plenty of time, then you could look into your planning again.