I also had DCIS - high grade. However with my wide local excision I did not have clear margins and mine was also classed as "extensive"...
I have since had a sentinel node biopsy and that's all clear..
Because DCIS is very early and there are a lot of variables the treatment plan can be very different for every one...
Age, family history and the nature and pathology all play a part. I have heard that what you have been advised for treatment is often suggested but if you are unsure you need to keep asking questions until you are comfortable.
There is some great information on DCIS on both cancer council website and the national site as well. Time is on your side and you don't have to make any rush decisions but take a couple of weeks to do some research about what this diagnosis means for you and your treatment and your future monitoring.
My circumstances are a bit different to you however my treatment is mastectomy - don't panic because my situation is different... I have learnt that this is not a one size fits all and that there are a lot of variables that change treatment options.
I personally needed to be really informed in order to ensure the decisions I was making were right for me.
Good luck - this is a great site for asking questions and sharing information - good luck with your journey
Chris xx