The two options you list are very different.

Usually coaches provide content + many times group coaching (also called membership programs).

This means using WordPress + a membership plugin.

I tell my client to avoid WooCommerce, as it's far more complex to use than you'll imagine at first glance.

Using Shopify, means Shopify owns/controls/dictates your entire process, so I never use this platform.

Start with WordPress.

Look for someone who can consult with you about both business practices and technology, like WordPress.

If you can't find anyone like this, you can book a call with me. Either I can help or point you to someone who can.

Disclaimer: I run a high speed, WordPress hosting company + consult with my clients about topics like end-to-end marketing (from ad spends to conversions) + best practices for site scaling (as traffic increases)...

I say this because I've seen people use both WooCommerce + Shopify incorrectly + trying to escape either of these systems, after they're being used... is painful...

Like getting off hard drugs.

Better just never start.