The type of medication you are started on should be after your neuro discusses the medication options (ideally)

People with young onset PD are often started off on agonists, or given the option to do without medication for a while, and sinemet is reserved for later.

With older onset it is sometimes seen as not so important to defer taking sinemet, as keeping moving is often an important factor.

PWP should have some input into the way that the decision is made, once options are discussed.

Ask questions, if the answers are not clear ask again, keep yourself well informed.

Some people are highly sensitive to levodopa, and do develop side effects, others are less so. From the many discussions that have taken place here and on other forums it seems low doses, at regular times, and eating major protein meals late in the day to avoid them interfering with uptake of ldopa can give people a better chance.

It isn't possible to predict who will develop side-effects or sensitivities and when. It it not that levodopa stops working either, as PD is progressive, and a person may need to adjust upwards. The real problem is that once the side effects start to happen it becomes a balancing act between too much (more side effects) and too little (not enough on time).