From the Jain point of view, Jain Dharma is considered beginningless and eternal—it is not seen as founded at a historical moment.

The term “Hinduism” is a later name for a broad group of Indian traditions. So if you ask in a historical sense, Jainism is generally regarded as older as an independent śramaṇa tradition, while Hinduism as a single labeled religion is much later.

In simple words:

• Jainism: eternal, beginningless in Jain belief
• Hinduism: later umbrella term for many traditions

So, Jainism is older in the Jain understanding.