Its slightly below average. I would say keep working at it, Gold is generally considered average / slightly above average.
And for an explanation on how it works. There are divisions as follows. Each represented through 5-1. 5 Being low, 1 being highest in the tier.
Bronze (Noob land)
Silver (starting point for most)
Gold (Average)
Platinum (Above average)
Diamond (Great player, almost at the top)
Challenger (Best of the best) / Master (Same as Challenger, but the ones that aren't the absolute best in that tier)
Winning games will give LP, losing games loses LP. When at 100 LP you will be qualifed for a promotion to the next highest level in that tier. (Just win 2 of your next 3 games)
This is just a brief summary of the ranking system. Hope it helps.