If you can take a local help of knowing how much it might cause to travel in between two destinations, by a local, friend or hotel front desk, you will be a smart traveller. Unfortunately theft is quite common in places visited by tourists, but violent thefts hardly ever occur. For joining send your details and photos.
I'm over 18 years. It is advisable or better to agree on the fare beforing getting inside an auto or a taxi. For a foreign customer the negotiating situation to make the price as low as possible might be more challenging than for local men.