I created my main in 2002, and stopped playing in 2008. I downloaded osrs mobile, signed into my main and it made me create a new profile. Now even if I type my mains account and password it will just send me to my new account. Is there any way to get on my main on osrs mobile?
The game you remember playing has evolved over the years into RuneScape - which is only in Beta for mobile gamers (and the spots for that beta have filled). If you log in there, you should find all of your stats from before. I see your account having 1254 total level there.
Old School RuneScape was released as a brand new game in 2013 - everyone started fresh there, and there was no way to move stats or items over. If you wish to play Old School RuneScape, you would continue with a new game profile, however certain things, such as your friends list, will be intact from before.
The game you left in 2008 is not the current Old School Runescape, you were playing what RS3 is now. OSRS is not the game you played way back 2002-2008, upon logging-in, you basically starts from scratch.