You won't ever learn anything until you lose. Lost games are to be studied; they are your best path forward. Everyone loses games. Try to think differently.. instead of "losing" think of it as "being trained by a better player".
Playing on a board is different than online. You have to physically hit a clock. The pieces look very different in real 3-d. You can see your opponent and facial expressions, gestures, etc. There are distractions, noise, people walking around. If you want to play that way, get used to it early so these things become natural to you.
i'm 18 years old and i started chess before 2 months and my rating is 1125 but in chess.com my rating is just around 800 , anyway i was playing checkers before chess , and i always i have the same problem is fear from losing , i know it's just a game , a complicated game , but this fear come to me when i always play , i've never played a real chess (i don't have a chessboard and there is no clubs close to me that they teach chess) , if i fear behind this screen how it will be if i play real game ? i think my heart will stop , anyway (please excuse my english)