I Could Not Sign Up for Lemon8 Even Though I Am 18

I heard good things about Lemon8 from a few friends, so I tried to sign up recently, but it didn't go well at all. I put in my birthday correctly—I'm 18—but the software kept telling me I couldn't join. I checked my information again and even reinstalled the software a few times, but nothing worked. I felt like I was being locked out for no reason, and there was no one or anything to assist me figure it out. I was pretty annoyed with the procedure, especially considering this was my first time using the site. I didn't expect everything to go perfectly, but not being able to even sign up made me wonder how trustworthy and easy to use this app truly is.