First off I would like to congratulate you for
entering the multiverse. I have a hard time knowing what format you are trying to build in. The standard format is Innistrad to Dragon's Maze as of this post and will soon be changing on September 27 when Theros comes around. Your deck seems rather good for a starter but one major card I would change is
Sands of Delirium. Sands is a card that is tailored more for a "mill" deck. Your deck is more focused on early ramp into large creatures to beat in the red zone. Due to this I believe that both
Wall of Vines and
Wall of Wood should be cut as they are inefficient walls. I would love to suggest new cards to replace the old but I still cannot figure out what format you wish to play in. Best f luck Planeswalker!