I'd say wait a bit for now. If the shop won't do exchanges, you can get a starter kit pretty inexpensively. When you vaped your friend's kits, did you get a lot of vapor? A little vapor? You can put different
tanks on your two battery mod (if you get one of those) should you care to, you'll just have to adjust the wattage to meet your different tank's needs. You can get a MTL tank (high resistance, low watts, usually higher nic, but less vapor) or a DL tank (more cloudy, more vapor, inhaled directly into the lungs, usually less nicotine). Some users like both, which is why it's nice to be able to change tanks.
If you really like the idea of a mech mod, you can keep yours until you are ready and have enough experience to vape it....
Anna