Not that you asked but you need to ride a lot more than 100 miles a month. I do that in a week.

100 miles a month at say 3-4 rides per week = ~6 miles per ride

Like others have said, don't do any interval or speed training until you have more base miles.

I like to ride a regular ride of 14-22 miles and a long ride of 30 -60 miles on the weekend. I ride about 5 days a week.