score:5
There is no rule against traveling solo.
There is no rule against traveling for the first time.
If you use a visa agent then you should make really sure that you understand what you sign and that it is the truth. Honest visa agents help their clients with confusing application forms, for a fee. Dishonest visa agents enter lies for their clients, but it is the client who suffers if the lie is found out.
Regarding your application, ask yourself if you can reasonably afford the trip, and if someone who doesn't know you has reason to believe that you are no illegal immigrant.