Hi E.,
As many others have mentioned, this is a very personal decision and entirely up to you and your husband - it's not appropriate for others to think they have any say in the matter, much less for them to be trying to "guilt" you about it, if they are doing that (that's the way I understood what you had written about family members). If anything I'd give those folks' input even less consideration because they obviously don't have your best interests nor those of your family at heart - if they DID have, they wouldn't be handing out guilt. Children are a blessing - not to be used as a source of guilt!!
As far as timing...I have pondered the same thing (our daughter was 2 on Oct 30, 06) and have also done some research on the topic (that's my usual approach :) ). I was very reassured to find that the common recommendation of psychologists is that children be spaced at least 3 or 3.5 years apart from the first one (and this would apply with subsequent ones, if possible). The main reason for this is to not add stress to the early formative stages of a child's life. Having children closer - especially having a new baby when a child is near 2 - risks additional and unnecessary stress for both parents and child.
Think about how tired you felt at times during your pregnancy (if you did! I know I did!) and how very tired and sleep deprived you felt in caring for a newborn, and how much special "bonding" time you wanted and needed with that new baby so you could get to know one another. Now imagine trying to devote the time and attention a 2 year will need and deserve as well as caring successfully for another newborn, not to mention self-care and attention to your marriage as well. I wouldn't want to be in that situation and I certainly wouldn't want to subject my precious little girl to it (thus we don't have another baby yet!).
Even before I read the research I did, a 3 to 5 year interval has always been my personal preference about child spacing for a lot of reasons. Not to criticize anyone that thinks differently, of course - but as I mentioned above, I think it would be unfair to my little girl to have a new and totally needy little baby to care for while she is still in a part-baby stage of life (which toddlerhood is!), going through so many changes and working to master so many of life's most basic skills, and emotionally still needing me so much.
She is actually very interested in babies and likes them - but when I hold one of our friends' babies and play with her, she always needs some reassurance and to be "included" at some point during that interaction. She's not mean about it at all, just sidles over and wants to be sure she still has her "place" with me, and her desire makes perfect sense to me.
What others do may not work for you - and that's okay. :) If your truest belief is that you should have a large family with lots of kids close together, and you're realistic about your energy and what you will have to give, that could work for you. If what you see when you look at your situation is that it would be too risky emotionally for your young daughter to add a new child so soon, then you can wait for a few years and know that you are doing the best thing for her and any subsequent kids.
I think you are really being a good mom (and your h a good dad!) to be concerned with this and giving it serious thought instead of acting impulsively! Please, try to release the stress and stop worrying what others may think - do what YOU prayerfully decide is really best. Your daughter is blessed to have thoughtful parents who are weighing such important life decisions so carefully and who are thinking of their child's best interests. Relax and enjoy parenting her exclusively while you can, with no other kids that also need your attention. Believe me, this next year will go by QUICKLY and she will be 2...and then 3...and by then you may be more settled about adding a new baby to the mix.
It really all comes back around to you and your husband's judgment about what will be best for your daughter and for your family life. Pray about what to do and wait patiently for God's guidance. There's no rush! :) Enjoy this season of life with your husband and daughter.