I had the exact same problem when i was in the level range of 10-20. Before that, you should have done alot of PvP because you are all on even grounds without runes. Once i reached level 15, I couldn't win PvP NO MATTER WHAT because most of the time it matched me with people over level 20, so they had somewhat-full to full rune pages. If you are afraid of PvP just do some more bot games until you reach level 20, buy some runes, then you should be better off at playing PvP. Hope this helped.
EDIT: I saw your comment about getting 0 deaths in intermediate. Totally not true. I still go 10-20 kills and 2-6 deaths in intermediate. Dont compare humans with bots.