i suggest you go to a gym
1)You can make friends and ask advice from those who know
more(although some people will tell you urban legends lar)
2)You will out-grow the weights you have at home
3)The gym has more proper equipment like benches and power-racks
and you can add in some machine work as well(but dont be too
over-reliant on machines, its not good)
4)More motivation, you see some huge ass guys carry heavy weight
and it encourages you to work harder and eat harder.
5)Prevent overtraining, sometimes when you have the dumbbell
infront of you.You tend to overdo and strain yourself.
6)Feeling of satisfaction.If you did a great-workout you will feel
that your trip is worth it and would continue working out in the
gym.
7)Because i said so 