Yes, a Deltiologist. It is such a formal name for someone who collects and studies postcards. Though most people who collect things will need to study and do significant research on what they are collecting and how to find it, clean, categorize, etc. So, Deltiologist it is but I prefer to just be called a postcard collector.
Although I have my favorites, I have always been an indiscriminate collector. This has advantages and disadvantages; you are just starting out it may be to your benefit to focus on one subject or type of postcard to collect.
Collections that focus on a specific characteristic of the card are specialized, everything flows and often they can be easily displayed in some kind of natural order. A person that has a specialized collection also has the advantage of getting to know that certain type of card very well, they know what to look for and what to look out for. They also have the "thrill-of-the-hunt," meaning that finding their specific card is much harder and when they do the satisfaction is much greater. There are too many different subcategories of postcards to include all, but I would like to list some to give you a sense of why I enjoy postcards so much.
Collecting postcards based on what is on the back. Some collections will include only undivided backs. Prior to 1907 postcards had only one side to write the message on; the picture side. The back side was only to be used for the address and the postage. Note: collecting cards that have writing on the front of them from this period is acceptable since that was how they were designed.
Note that there was plenty of room left on the front to write the message
After 1907 they started the divided back leaving room for a conversation on the backside of the card to preserve the image on the front. Unfortunately you will find many of the earlier divided backs still have writing on the front of the card; old habits die hard.
There are many collections based on how the card was cancelled. Briefly; some postcards sent from rural locations were cancelled by hand with a pen, Source Marking meant it was cancelled while traveling by rail, ship or steam boat, fancy cancelation marks are just like they sound - Fancy, and Killer which completely covers the stamp with a black ink. There are many more not mentioned. People may also look for specific post offices that are no longer in existence making it more rare.