Looking for advice

This is a long post so here goes.. I ran a travel co up until COVID when it went out of business. 10 years of hard work gone which has been tough to deal with. I'm still not fully recovered and have struggled to find anything that really gets me 'going'. So over the course I the last few years I've tried (and failed) on a number of small, mainly tech products using Bubble to build a MVP. My only success was a walking holiday co which I sold as it was too seasonal. To make ends meet I've been doing web design which I really don't enjoy....I love the business creation and development. My connections in the industry have opened a few opportunities and I had started building a tool which creates courses using AI and will be incredible for our specific area. But, it needs to be fully coded so I am now working with my Brother (who is a full time coder) to build this. We now have a working prototype and have 2 clients for certain including a major tourist board. Others are interested too and hoping to get some firm commitments soon. I am a realist and this isn't going to be built quickly but we want to build ourselves. It has greater scope for other industries and perhaps a self serve platform too and this is part of our marketing plan. Having spent time on other projects, I am very cautious but feel the very early validation is a positive. In addition to this, I'm also setting up another tour company which can begin trading immediately (as have all contracts etc) in order to fund some of the development with the aim of ultimately selling when the software is live and generating revenue. My question is...I feel a huge sense of anxiety and nervousness about spending yet more time on another project. Perhaps this time I'm making the right steps by validating first then coding plus there are a number of other applications for it. Is this a normal way to feel? I had relative success with my last co in my 30s, since I turned 40 life has been way more challenging.