It's hard to give a single answer to this question, as there are many factors to consider, such as your personal style, the style of the person you're meeting, and the nature of the occasion. However, here are some general tips that you might find useful:
Keep it simple: It's best not to overdo it on the first date. Discreet, elegant jewelry will generally be a better option than showy or busy jewelry.
Pay attention to the outfit: make sure that the jewelry you wear suits your outfit. If you're wearing a dressy dress, a more sophisticated piece of jewelry might be appropriate, while a more casual look might be better suited to a simpler piece of jewelry.
Choose jewelry that suits you : Wear jewelry that reflects your personality and makes you feel comfortable and confident. If you are a discreet and reserved person, a discreet jewel may be better suited to your style. If you are more daring and eccentric, you could opt for a more showy piece of jewelry.
Don't worry too much: this is just a first date, so don't put too much pressure on yourself. Wear a jewel that you like and that makes you feel good, but remember that it is above all your personality and your conversation that will make the difference.
Ultimately, deciding what jewelry to wear on a first date depends on many factors and there are no hard and fast rules. Trust your judgment and your personal style, and remember that it's your personality and your conversation that matter most.