Either! Both! Really, you should get the deck that is right for you. Tarot and oracle decks offer different things, and one might be better for your needs than the other.
Because tarot is based on one universal system (with some variations), once you learn the basics it’s very easy to start reading! There are tons of materials to help you learn, because tarot has been around so long and is so popular. If you’re looking for a deck which many other people understand, one with lots of lore to explore and so many interpretations, tarot is for you.
Oracle decks, on the other hand, can be much more straightforward. Without one system to follow, oracles are much freer. Each one is different, so you can just pick one up and it’ll tell you exactly how to read the cards. Often, oracle decks have their meaning written right on the card in the form of keywords. You can also pick a theme that really chimes with you. If you want a deck that’ll give you a feel for divination without you having to learn a system, you might want an oracle.
In terms of reading the cards, tarot decks have multiple interpretations and layers of nuance. This means you have to practice, but once you get used to it the tarot is very versatile, making for readings that are very deep and have lots of connections.
Oracle decks, on the other hand, are more intuitive. They can be gentler than tarot, and thanks to how different each deck is, you can really tailor your experience. Most decks do lack the depth of tarot, because tarot’s level of complexity and historical significance is very hard to replicate — and many oracle creators don’t want an overly complicated deck. However, this can give your readings a directness and clarity that tarot sometimes lacks. (After all, there’s always another interpretation with tarot!)
Basically, each have their advantages, especially for a beginner. Tarot has a universal system that means that you can read any tarot deck (mostly). Oracles are more quickly understandable, but sometimes lack depth. Ultimately, I would advise you just pick the one that you like the look of. You really can’t go wrong!