Hi. New here

In April I buy 30000 BCN coins at 91 satoshi
I must keep it until get higher price, or I sell it?
Never sell when you're loosing that much, at least not if the whole project isn't dying. It will definitely get back to 90. Just hold till then.
Great guess. I also have the opinion that the project should return to the level of 90-100 Sat in the near future. A new quick-sync wallet would be very useful for us now.