Start with the instrument you have
Find the model name, count the keys and check whether the sound changes when you play more gently or firmly. Do all the keys work? Does the instrument stay steady on its stand? A clear description can help a teacher judge whether it suits the first assignments or whether a different instrument would be more practical.
Know what the feature words mean
Touch-sensitive keys can change the sound in response to how you play. Weighted action concerns the resistance and feel of the keys; it is not the same thing as touch sensitivity. Manufacturer specifications are useful here. For example, Yamaha describes its beginner P-145BT as having 88 weighted, touch-sensitive keys. That is an example of the terms, not a requirement to buy that model.
Consider room to grow
A full-size, 88-key weighted digital piano is worth discussing for a student planning to continue, but a purchase should fit the budget and use case. A shorter keyboard may support some early tasks while limiting later repertoire or two-handed patterns. Ask the teacher which limitation matters now rather than assuming every inexpensive instrument is unsuitable.
Do not forget the physical setup
An instrument on a high dining table and a chair that leaves the player reaching upward can make practice awkward. Plan a stable stand or furniture surface, appropriate seating, space for music and an accessible power supply. These are part of the setup, not decorative extras. Avoid balancing a device where it can fall onto the keys.
Ask before buying used equipment
Check every key, the power connection, speaker output, pedal connection and any accessories included. Confirm the exact model rather than relying on a listing that only says “piano keyboard.” A teacher can help interpret the specifications; an equipment fault may need a technician or the manufacturer rather than a lesson solution.
Choose for the lesson, not the advertisement
You do not need hundreds of voices or an app subscription to ask about a first piano lesson. Bring the practical details to your teacher and decide on the smallest sensible next step. This guide is a buying checklist, not a current price comparison or an endorsement of a particular seller.