[MichaelCollins]

Look at what other similar projects have been doing, and if it's been working out well enough for them. And if you are the sole copyright owner, you're not locked into your choice. You can either refuse community contributions or make them sign over the copyright to you. Then you're free to distribute your software under another license going further.

Proprietary software doesn't save you from having to make decisions like this. Proprietary software can be licenced under many different terms. Are you going to sell perpetual per-seat licenses? Subscriptions? Selling updates? Support contracts? Avoiding future regret is always going to be a speculative affair.