My non-Bitcoin friends have started to ask me if now, "is it a good time to invest/HODL in Bitcoins". Believe it, or not, I didn't have an answer.
What should I tell them, Bitcointalk?

Tell them yes, and tell them not to panic if there is a big correction after this.
They are interested to hold so they hold make sure they can hold for a longer period of time and will not panic when the price will dump.
Also, tell them do some research, the reason why most newbie fail is because of their timing, their wrong timing instead, suppose to be this time is the time to sell not to accumulate, but they come it, they like to play the FOMO, and actually that's aright as long as they are ready to hold.