According to Islam,is having sex before marriage forgiveable?And is blowob haram according to Islam?

I don't know what the Koran says about that,. but I have a circle of devout Muslim friends... and I know both occur quite frequently in the Islamic community as it does outside the Islamic community as well. And that was told to me by a muslim woman about other muslim women (they talk among themselves which is how she knows this). They didn't appear to be worried about it and they are devout Muslims.

But do what feels right to you. Don't allow yourself to be pressured into anything YOU aren't ready to do by anyone. If that means abstinance... then be true to yourself.