I can only find the answer to one of your questions. Your license will turn into a senior license on your 18th birthday:
If you do not have an MV-285, the DMV automatically changes your driver license from Class DJ to Class D on your 18th birthday. The DMV automatically mails you a new driver license that indicates “Class D”. You will not get this document faster if you visit a DMV office.
On your 18th birthday, your driver record indicates that you are a Class D driver. There is no need to wait until you have your new Class D driver license before you drive as a senior driver. You can drive as a senior driver on your 18th birthday. Here
Also, the points are calculated based on the date of the violation, not the date of conviction (court):
The DMV computer system automatically calculates your point total as follows:
-You must be convicted of the traffic violation for the points to be added to your point total, but the calculation of your point total is based on the date of the violation, not the date of the conviction.
-The points for violations that all occurred within the last 18 months of one another are added together to calculate your point total.
-The record of the conviction, and the points, are listed on your driver record for as long as the conviction remains on your record. The information about the conviction and points is not removed after 18 months from the violation date. Only the calculation of your point total changes. Learn more about convictions and your driver record. (from the same website above).
My only advise to for you is to go to traffic court and appear before the judge. That will give you your best chance of (1) reducing your ticket and (2) understanding the consequences of the conviction.
Also, you can remove up to 4 points and receive a 10% insurance premium reduction after attending a safe driver course.