because everyone's a critic
You want to be a writer.
Dammit, you are a writer!
As such, you'll need a cadre of readers to test your scenes and completed work. The more you write, the more content you'll have that needs perusal and critiquing. But where to turn? Friends and family will likely love your work on principle and turned a blind eye to poor writing, plot holes and weak characterization. What you need are people who can be objective and who are as dedicated to the craft of writing as you are so that they will invest time in reading your work by choice, not as a personal favor.
Writing groups were created for this very purpose... and frankly, one could say the same about Starbucks, where so many groups choose to gather and nurse lattes while waxing literary.
Not only will your fellow group members critique your work, they will offer advice and camaraderie. Chances are, they've been in your shoes and faced many of the same challenges as you. Plus, you get the benefit of reading their work and learning from their successes and opportunities for improvement.
The following are a few links to help you find the group that's right for you—whether as an in-person Meetup or digital gathering: