Just got diagnosed with glaucoma at age 23

I haven’t been to the eye doctor in about 2 years due to not having insurance. There was never an issue with my eyes in the past just astigmatism and nearsightedness. I went today to a new optometrist for the first time and got diagnosed with glaucoma. I’m 23 and I don’t know anyone in my family who has had it so I’m totally caught off guard especially since my last optometrist never caught it. I haven’t gotten eye drops yet because it’s not at an extreme risk right now, but eventually they want to do an ultrasound and to come back in 3 months. Is there anything I could’ve done that caused this? Or anything I can do to help my glaucoma? I’m really scared and don’t know anything about this.

(Also I smoke mrijuana everyday, does that have any impact on me having glaucoma)