If I do ROTC and commission Active Duty, will my Time in Service continue from my Enlisted time in the National Guard?

There are two types of credit for service, credit for pay and credit for retirement. ROTC does not earn any credit in itself, but your membership in SMP will earn credit for pay since it is a reserve status. There is no enlisted or commissioned difference, it is all considered credit for pay.
If you are activated your retirement will be based off 20 years of active service. You can retire at 20 years, but your percentage will be based off your pay years.

Your time in service will count towards your pay but not for retirement. However, time served during initial entry and annual training does for retirement.

As long as you are an SMP it will count for your Pay.

That requires a smart person who is update on cadet status. Time in ROTC did not count for Time in Service prior to SMP. I could guess, but that won't do you any good. SMP puts a whole new spin on this question. Your NG personnel type should be able to answer that question for you. I'd ask them to provide a good reference for you.

I didn’t know that my SMP time, outside of AT’s, would count towards my “pay years” when I go back on Active duty. So I guess I’d get O1E with over 8 years since I had 6 prior active enlisted years on active duty before my 2 years of SMP. If I’m correct then that’s a nice surprise.

Everything but SMP time.

All time counts toward 20. Reservists time only drills summer camp and school days make the count. But things are funny with ‘it’s helping pay

Your enlisted time does count as time in service. So if you go active duty, you would have higher pay rate than a 2LT who did not enlist. However, when you commission, you do incur a new 8 year service obligation. So you enlisted time does not offset that.

Your Time in Service will be figured from you Pay Entry Base Date on your current LES if you are SMP during your ROTC time. If you go Active Duty, only your active duty time will transfer to years in service, so you will get credit of Initial Entry Training, AT, full time military schools and Federal Deployments day for day, but nothing for IDT drill training or membership points . What makes that even more confusing is if you retire, you can get one day credit for every point you earn in the Reserves or National Guard for pay purposes for retirement. So with six or seven years in the ARNG by the time you commission, it could add four or five percent, depending which version of retirement you are on.