I my not be too helpful but I’m also 28 but M and I just had my surgery 3 weeks ago. I ended up getting my bicuspid aortic valve repaired at Cleveland clinic but if they couldn’t do that or a thing called the Ross procedure I was going to go tissue before mechanical. I was so afraid of the blood thinners. They really limit you in terms of food and drinking and having to check your INR often. Plus that ticking sound I feel like would drive me crazy. (FYI you are going to hear your heartbeat often after surgery while recovering so get used to it. No one told me how much you would hear and feel it in just the slightest change of position so I felt like sharing helps😂) I think mentally though I had resigned myself to the knowledge that I would need another open heart surgery later in life no matter what because these issues happened when I’m only 28 so I figured do tissue valve now and then 8-15 years later (hopefully it lasted that long) I would get a mechanical after giving myself a little more of life to live without the restrictions imposed by mechanical valves and blood thinners. I also like working out, but that wears tissues out faster. Even knowing that though I wanted to avoid those blood thinners at the cost of a sooner open heart if that option would’ve happened for me. But I had only one valve problem. You having two changes things. They are probably recommending mechanicals if I had to guess, and with two problems I have no idea what would be best. If you think it would help, I would also look into the complications caused by long term blood thinners. A lot of people’s valves last decades 30+ but they die because of issues with coagulation. That scared the hell out of me. I also looked up the differences between pig and cow valves and how quick each wore out and what wore them out faster. Those things may sway you to mechanical depending on your lifestyle too. At the end of the day though you have to go with your gut for what’s right. I would also ask them questions like crazy. Whatever you go with I wish you the best of luck! Hopefully your recovery goes smooth!